A gear and rack lifting hydraulic system based on an offshore platform and a control method thereof

Abstract

A kind of gear and rack lifting hydraulic system based on ocean platform and its control method, including multiple piles, multiple hydraulic oil pumps and multiple lifting devices, each pile is sleeved with a lifting device, and the pile is driven in cooperation with the gear on the lifting device through the rack arranged thereon, the lifting device includes main lifting mechanism, auxiliary lifting mechanism and isolation valve group, the A cavity and B cavity of main lifting mechanism are respectively connected with the A1 port and B1 port of isolation valve group, the A cavity and B cavity of auxiliary lifting mechanism are respectively connected with the A2 port and B2 port of isolation valve group, and the on-off between the A1 port and A2 port of isolation valve group and the on-off between the B1 port and B2 port are all controlled by isolation valve group control valve.This design can not only control the size of system output torque and rotating speed by the on-off of isolation valve group, but also can improve the output oil volume of hydraulic oil pump by built-in oil supplement pump, effectively improve system output power.

Description

Technical Field

[0001] This invention relates to a lifting system, and more particularly to a gear and rack lifting hydraulic system for offshore platforms and its control method. Background Technology

[0002] A jack-up offshore platform is a type of offshore work equipment commonly used in shallow sea areas. Due to its advantages such as large load-bearing capacity and low cost, it is widely used as an auxiliary living platform for marine engineering equipment such as oil and gas processing platforms, living platforms, and wind power installation vessels.

[0003] Existing jack-up offshore platforms typically consist of a fixed pile frame, legs, and a hydraulic lifting system. The fixed pile frame is mounted on the legs and can move up and down along the legs under the drive of the hydraulic lifting system. For jack-up offshore platforms used as auxiliary living platforms, the lifting frequency is relatively high because they need to change their operating locations constantly with different oil production points. Therefore, their lifting systems generally adopt a rack and pinion lifting form.

[0004] In a rack and pinion self-elevating offshore platform, each leg's rack and pinion lifting system consists of multiple lifting units. Each lifting unit is driven by a motor brake, which engages a pinion gear with the leg's rack to achieve the leg's vertical movement. Each lifting system is equipped with an integrated hydraulic pump station to simultaneously supply oil to all motors and brakes of that leg. As the operating location of the self-elevating platform changes and the working environment varies significantly, the requirements for oil production equipment costs and platform lifting speeds are also increasing. When the platform is lifting, the hydraulic system is under heavy load, and the lifting system operates at a slow speed. However, when the floating legs of the platform are lifting, the hydraulic system is under lighter load, requiring the lifting system to operate at a high speed.

[0005] Currently, with the increasing workload of platforms, jack-up offshore platforms typically employ multiple large-displacement motors to drive the load. When switching to high-speed operation, the lifting speed is often increased by increasing the pump station's output flow. Some jack-up platforms also use variable displacement motors to control the platform's lifting speed; by switching the variable displacement motors to a smaller displacement state, the lifting speed of the jack-up platform can be increased. While both of these solutions can use hydraulic lifting systems to drive the offshore platform's lifting and lowering to meet the needs of offshore operations, they still have the following drawbacks:

[0006] 1. Increasing the output flow of the pump station requires correspondingly larger pump valves and pipe fittings, resulting in higher manufacturing and maintenance costs.

[0007] 2. The method of controlling flow through a variable displacement motor has a more complex structure, a higher failure rate, and a higher cost compared to a fixed displacement motor, resulting in poorer overall system economy.

[0008] The information disclosed in this background section is intended only to enhance understanding of the overall background of this application and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0009] The purpose of this invention is to overcome the shortcomings of existing hydraulic lifting systems that have high structural costs, complex structures, and high failure rates in achieving power regulation. This invention provides a gear and rack lifting hydraulic system and its control method based on an offshore platform that achieves power regulation with lower structural costs, simpler structure, and lower failure rate.

[0010] To achieve the above objectives, the technical solution of the present invention is:

[0011] A rack and pinion lifting hydraulic system includes: multiple legs, multiple hydraulic pumps, and multiple lifting devices. The number of hydraulic pumps is the same as the number of lifting devices. Each leg is vertically fixed to the ground. Multiple racks are vertically arranged on the sides of each leg, evenly distributed around its circumference. Each leg is fitted with a lifting device. Each lifting device is supplied with hydraulic oil by a hydraulic pump. Each lifting device includes a main lifting mechanism, an auxiliary lifting mechanism, and an isolation valve assembly. The main lifting mechanism includes multiple main lifting mechanism units, and the auxiliary lifting mechanism includes multiple auxiliary lifting mechanism units and an isolation valve assembly. The main and auxiliary lifting mechanism units have identical structures. Gears that mesh with the rack and pinion transmission are provided on the power output ends of each main and auxiliary lifting mechanism unit. The gears on the main lifting mechanism unit and the auxiliary lifting mechanism unit rotate synchronously. The first oil port of the hydraulic oil pump is connected to the A chamber of each main lifting mechanism unit. The A1 port of the isolation valve group is connected to the A chamber of each main lifting mechanism unit. The A2 port of the isolation valve group is connected to the A chamber of each auxiliary lifting mechanism unit. The second oil port of the hydraulic oil pump is connected to the B chamber of each main lifting mechanism unit. The B1 port of the isolation valve group is connected to the B chamber of each main lifting mechanism unit. The B2 port of the isolation valve group is connected to the B chamber of each auxiliary lifting mechanism unit. The connection and disconnection between the A1 and A2 ports of the isolation valve group are controlled by the isolation valve group control valve. The connection and disconnection between the B1 and B2 ports of the isolation valve group are controlled by the isolation valve group control valve. The isolation valve group control valve is a two-position three-position normally closed solenoid valve. The oil inlet of the isolation valve group control valve is connected to the control oil port of the hydraulic oil pump.

[0012] The hydraulic pump includes a closed-loop main pump and a motor. The closed-loop main pump is a hydraulic pump whose opening and rotation direction are controlled by a handle. The oil inlet of the closed-loop main pump is connected to the oil tank. The first oil outlet of the closed-loop main pump is connected to the first oil inlet of the main lifting mechanism and the auxiliary lifting mechanism. The second oil outlet of the closed-loop main pump is connected to the second oil inlet of the main lifting mechanism and the auxiliary lifting mechanism. The power output end of the motor is fixedly connected to the main shaft of the closed-loop main pump.

[0013] The number of main lifting mechanism units within the main lifting mechanism is an integer multiple of the number of racks on the pile legs. The main lifting mechanism units are divided into multiple groups, with each group containing the same number of main lifting mechanism units as the number of racks on the pile legs. Each main lifting mechanism unit includes a fixed displacement motor, a first lifting solenoid valve, a second lifting solenoid valve, a first lifting relief valve, and a second lifting relief valve. Both the first and second lifting solenoid valves are two-position, two-position normally closed solenoid valves. The oil inlet of the first lifting solenoid valve is connected to the first oil outlet of the closed-loop main pump. The oil outlet of the first lifting solenoid valve is connected to chamber A of the fixed displacement motor; the oil inlet of the second lifting solenoid valve is connected to the second oil outlet of the closed main pump; the oil outlet of the second lifting solenoid valve is connected to chamber B of the fixed displacement motor; the oil discharge port of the fixed displacement motor is connected to the oil tank; the oil inlet of the first lifting overflow valve is connected to the oil outlet of the first lifting solenoid valve; the oil outlet of the first lifting overflow valve is connected to the oil outlet of the second lifting solenoid valve; the oil inlet of the second lifting overflow valve is connected to the oil outlet of the second lifting solenoid valve; and the oil outlet of the second lifting overflow valve is connected to the oil outlet of the first lifting solenoid valve.

[0014] The number of auxiliary lifting mechanism units within the auxiliary lifting mechanism is an integer multiple of the number of racks on the pile leg. These auxiliary lifting mechanism units are divided into multiple groups, with each group containing the same number of units as the racks on the pile leg. Each auxiliary lifting mechanism unit includes an auxiliary dispensing motor, a first auxiliary lifting solenoid valve, a second auxiliary lifting solenoid valve, a first auxiliary lifting overflow valve, and a second auxiliary lifting overflow valve. Both the first and second auxiliary lifting solenoid valves are two-position, two-position normally closed solenoid valves. The inlet of the first auxiliary lifting solenoid valve is connected to the first outlet of the closed-loop main pump. The oil outlet is connected to chamber A of the auxiliary quantitative motor; the oil inlet of the second auxiliary lifting solenoid valve is connected to the second oil outlet of the closed main pump; the oil outlet of the second auxiliary lifting solenoid valve is connected to chamber B of the auxiliary quantitative motor; the oil discharge port of the auxiliary quantitative motor is connected to the oil tank; the oil inlet of the first auxiliary lifting overflow valve is connected to the oil outlet of the first auxiliary lifting solenoid valve; the oil outlet of the first auxiliary lifting overflow valve is connected to the oil outlet of the second auxiliary lifting solenoid valve; the oil inlet of the second auxiliary lifting overflow valve is connected to the oil outlet of the second auxiliary lifting solenoid valve; and the oil outlet of the second auxiliary lifting overflow valve is connected to the oil outlet of the first auxiliary lifting solenoid valve.

[0015] The isolation valve assembly includes a first two-way cartridge valve, a second two-way cartridge valve, a first hydraulically controlled directional valve, a shuttle valve, a second hydraulically controlled directional valve, a third two-way cartridge valve, a first low-pressure shuttle valve, a first check valve, a second check valve, a second low-pressure shuttle valve, a back pressure check valve, a hydraulically controlled directional valve, and a throttle valve. The first and second two-way cartridge valves are normally open cartridge valves. The inlet of the first two-way cartridge valve is connected to chamber A of the fixed displacement motor in the main lifting mechanism, and the outlet of the first two-way cartridge valve is connected to chamber A of the fixed displacement motor in the auxiliary lifting mechanism. The inlet of the second two-way cartridge valve is connected to chamber B of the fixed displacement motor in the main lifting mechanism, and the outlet of the second two-way cartridge valve... The inlet of the first hydraulic directional valve is connected to the oil inlet of chamber B of the fixed displacement motor in the auxiliary lifting mechanism. The control ports of the first two-way cartridge valve and the second two-way cartridge valve are connected to the oil outlet of the first hydraulic directional valve. The control port of the first hydraulic directional valve is connected to the oil outlet of the control valve of the isolation valve group. The unloading port of the first hydraulic directional valve is connected to the oil tank. The oil inlet of the first hydraulic directional valve is connected to the oil outlet of the shuttle valve. The first oil inlet of the shuttle valve is connected to chamber A of the fixed displacement motor in the main lifting mechanism. The second oil inlet of the shuttle valve is connected to chamber B of the fixed displacement motor in the main lifting mechanism. The oil outlet of the shuttle valve is connected to the oil inlet of the second hydraulic directional valve. The control port of the first hydraulic directional valve is connected to the outlet of the control valve of the isolation valve group; the outlet of the second hydraulic directional valve is connected to the control port of the third two-way cartridge valve; the discharge port of the second hydraulic directional valve is connected to the oil tank; the first outlet of the third two-way cartridge valve is connected to chamber A of the auxiliary lifting mechanism; the second outlet of the third two-way cartridge valve is connected to chamber B of the auxiliary lifting mechanism; the first inlet of the first low-pressure shuttle valve is connected to chamber A of the fixed displacement motor in the main lifting mechanism; the second inlet of the first low-pressure shuttle valve is connected to chamber B of the fixed displacement motor in the main lifting mechanism; and the outlet of the first low-pressure shuttle valve is connected to the inlets of the first and second check valves. The first check valve's outlet is connected to chamber A of the auxiliary lifting mechanism; the second check valve is connected to chamber B of the auxiliary lifting mechanism; the first inlet of the second low-pressure shuttle valve is connected to the outlet of the first two-way cartridge valve; the second inlet of the second low-pressure shuttle valve is connected to the outlet of the second two-way cartridge valve; the outlet of the second low-pressure shuttle valve is connected to the inlet of the throttle valve; the outlet of the throttle valve is connected to the inlet of the hydraulically controlled directional valve; the control port of the hydraulically controlled directional valve is connected to the outlet of the control valve of the isolation valve group; the outlet of the hydraulically controlled directional valve is connected to the inlet of the back pressure check valve; and the outlet of the back pressure check valve is connected to the oil tank.

[0016] The hydraulic pump also includes a control pump, the main shaft of which is fixedly connected to the power output shaft of the motor, the oil inlet of which is connected to the oil tank, the oil outlet of which is connected to the oil inlet of the isolation valve group control valve, and the oil outlet of the isolation valve group control valve is connected to the oil tank.

[0017] The lifting hydraulic system also includes a brake control valve, which is a two-position three-position normally closed solenoid valve. The main lifting mechanism also includes a main brake, and the auxiliary lifting mechanism also includes an auxiliary brake. The oil inlet of the brake control valve is connected to the oil outlet of the control pump. The working oil port of the brake control valve is connected to the rodless chamber of each main brake and each auxiliary brake. The oil outlet of the brake control valve is connected to the oil tank.

[0018] The hydraulic pump also includes a built-in replenishing pump, the inlet of which is connected to the oil tank, and the outlet of which is connected to the inlet of the closed main pump.

[0019] The lifting device includes a main lifting mechanism, multiple auxiliary lifting mechanisms, and multiple isolation valve groups. The number of auxiliary lifting mechanisms is the same as the number of isolation valve groups. Each auxiliary lifting mechanism is paired with one isolation valve group to form an auxiliary lifting module. The auxiliary lifting modules formed by the auxiliary lifting mechanisms and isolation valve groups are connected in series end to end. Each auxiliary lifting mechanism's A chamber is connected to its corresponding isolation valve group's A2 port, and each auxiliary lifting mechanism's B chamber is connected to its corresponding isolation valve group's B2 port. One isolation valve group's A1 port is connected to each main lifting mechanism unit's A chamber, and another isolation valve group's B1 port is connected to each main lifting mechanism unit's B chamber. The remaining isolation valve groups' A1 ports are sequentially connected to their corresponding auxiliary lifting mechanism units' A chambers, and their B1 ports are sequentially connected to their corresponding auxiliary lifting mechanism units' A chambers. The lifting hydraulic system includes multiple isolation valve group control valves, with the number of control valves matching the number of isolation valve groups. Each isolation valve group control valve corresponds to one isolation valve group. The connection / disconnection between each isolation valve group's A1 and A2 ports is controlled by its corresponding isolation valve group control valve.

[0020] A control method for a gear and rack lifting hydraulic system based on an offshore platform, the control method comprising the following steps:

[0021] Step 1: Piling the offshore platform. The operator drives the vessel to transport the offshore platform to the work area. Once the platform arrives, the operator activates all the motors on the platform and simultaneously energizes the brake control valve, the first lifting solenoid valve, and the second lifting solenoid valve. The motors drive the corresponding closed-loop main pumps to start working. At this time, the operator drives the control handle of the closed-loop main pump to open the first oil port. The closed-loop main pump delivers hydraulic oil to the A chamber of each main lifting mechanism unit and the rodless chamber of each main brake. The extension rod of the main brake extends, releasing the locks of each main lifting mechanism unit. The gears of each main lifting mechanism unit rotate, causing the pile legs to move downwards. When the bottom of a pile leg contacts the seabed and is limited by the seabed, the force between the pile leg and the offshore platform causes the platform to rise. At this time, the motor corresponding to that pile leg is turned off. When all motors are turned off, the piercing step is complete. Depending on the working conditions of the offshore platform, the operator proceeds to the second step (raising the platform), the third step (lowering the platform), or the fourth step (lifting the platform).

[0022] Step 2: Elevating the offshore platform. When the offshore platform needs to be elevated, the operator activates all motors and built-in oil pumps, and simultaneously energizes the isolation valve group control valve, brake control valve, first lifting solenoid valve, second lifting solenoid valve, first auxiliary lifting solenoid valve, and second auxiliary lifting solenoid valve. At this time, the A1 and A2 ports and the B1 and B2 ports of the isolation valve group are connected. The operator then drives the control handle of the closed main pump, opening the first oil port of the closed main pump. The closed main pump delivers hydraulic oil to the A chamber of each main lifting mechanism unit, the A chamber of each auxiliary lifting mechanism unit, and the rodless chamber of each main brake and auxiliary brake. At this time, the telescopic rods of the main brake and auxiliary brake extend, releasing the locks of each main lifting mechanism unit and each auxiliary lifting mechanism unit. The gears in each main lifting mechanism unit and each auxiliary lifting mechanism unit rotate, driving the offshore platform upward. When the offshore platform reaches the designated height, the operator shuts off all motors and built-in oil pumps. At this time, the offshore platform elevation step is completed.

[0023] Step 3: Lowering the offshore platform. When the offshore platform needs to be lowered, the operator turns on all motors and all built-in oil pumps, and simultaneously energizes the isolation valve group control valve, brake control valve, first lifting solenoid valve, second lifting solenoid valve, first auxiliary lifting solenoid valve, and second auxiliary lifting solenoid valve. At this time, the A1 and A2 ports and the B1 and B2 ports of the isolation valve group are connected. The operator then drives the control handle of the closed main pump, which opens the second oil port of the closed main pump. The closed main pump delivers hydraulic oil to the B chamber of each main lifting mechanism unit, the B chamber of each auxiliary lifting mechanism unit, and the rodless chamber of each main brake and auxiliary brake. At this time, the telescopic rods of the main brake and auxiliary brake extend, releasing the locks of each main lifting mechanism unit and each auxiliary lifting mechanism unit. The gears in each main lifting mechanism unit and each auxiliary lifting mechanism unit rotate, driving the offshore platform to move downward. When the offshore platform reaches the designated height, the operator turns off all motors and built-in oil pumps. At this time, the lowering step of the offshore platform is completed.

[0024] Step 4: Offshore Platform Pile Lifting. When the pile legs need to be raised, the operator maneuvers the vessel directly beneath the offshore platform and activates all motors and internal oil replenishment pumps. Simultaneously, the control valves of the isolation valve group, brake control valve, first lifting solenoid valve, second lifting solenoid valve, first auxiliary lifting solenoid valve, and second auxiliary lifting solenoid valve are energized. At this time, the A1 and A2 ports and the B1 and B2 ports of the isolation valve group are connected. Simultaneously, the motor drives the corresponding closed-loop main pump to start working. The operator then drives the control handle of the closed-loop main pump, opening the second oil port. The closed-loop main pump delivers hydraulic oil to the B chamber of each main lifting mechanism unit, the B chamber of each auxiliary lifting mechanism unit, and each main brake... In the rodless chambers of the main and auxiliary brakes, the extension rods of the main and auxiliary brakes extend, releasing the locking of each main and auxiliary lifting mechanism unit. The gears in each main and auxiliary lifting mechanism unit rotate, driving the offshore platform downward. When the bottom of the offshore platform is at the limit of the top of the ship, the operator controls the disconnection between ports A1 and A2 and ports B1 and B2 of the isolation valve group through the control valve of the isolation valve group. At this time, the gears in each main lifting mechanism unit rotate, and the force between each leg and the offshore platform causes all legs to move upward. When all legs have risen to the designated height, the offshore platform lifting step is completed.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] 1. In a gear and rack lifting hydraulic system for an offshore platform, each leg is fitted with a lifting device. The legs are driven by a rack and a gear on the lifting device. The lifting device includes a main lifting mechanism, an auxiliary lifting mechanism, and an isolation valve group. The first and second ports of the hydraulic pump are connected to chambers A and B of the main lifting mechanism, respectively. Chambers A and B of the main lifting mechanism are connected to ports A1 and B1 of the isolation valve group, respectively. Chambers A and B of the auxiliary lifting mechanism are connected to ports A2 and B2 of the isolation valve group, respectively. The connection and disconnection between ports A1 and A2 and between ports B1 and B2 of the isolation valve group are controlled by the isolation valve group control valve. When the hydraulic system is under heavy load, the isolation valve group control valve controls the isolation valve group to open. At this time, the hydraulic pump supplies oil to both the main lifting mechanism and the auxiliary lifting mechanism. Each main lifting mechanism unit and each auxiliary lifting mechanism unit works synchronously, resulting in a large gear output torque and enabling slow-speed operation under heavy load on the platform. Therefore, this design can achieve slow-speed operation under heavy load by having all main lifting mechanism units and auxiliary lifting mechanism units work synchronously, effectively improving the maximum working load of the system.

[0027] 2. In the gear and rack lifting hydraulic system based on an offshore platform, when the hydraulic system load is low, the isolation valve group control valve disconnects ports A1 and A2, and ports B1 and B2. At this time, the hydraulic pump only supplies oil to the main lifting mechanism, controlling the flow rate of each main lifting mechanism unit's motor. Meanwhile, the auxiliary lifting mechanism units are interconnected through a second two-way cartridge valve, and the auxiliary lifting mechanism is in a follow-up state. The flow rate of each fixed-displacement motor is doubled compared to when the hydraulic system load is high. The gear output torque is low, but the rotation speed is high, enabling rapid movement of the leg under low load. Therefore, this design can control each main lifting mechanism unit to work independently through the isolation valve group, achieving rapid movement of the leg under low load and effectively improving system efficiency.

[0028] 3. In a gear and rack lifting hydraulic system based on an offshore platform, the present invention includes a closed-loop main pump and a built-in auxiliary pump. The closed-loop main pump is powered by a motor. The inlet of the built-in auxiliary pump is connected to the oil tank, and the outlet of the built-in auxiliary pump is connected to the inlet of the closed-loop main pump. When the hydraulic system is under heavy load, the built-in auxiliary pump can increase the output oil volume of the hydraulic pump, thereby increasing the system output power. Therefore, this design can effectively increase the system output power by increasing the output oil volume of the hydraulic pump through the built-in auxiliary pump.

[0029] 4. In a gear and rack lifting hydraulic system for offshore platforms, the lifting device may include multiple auxiliary lifting mechanisms and multiple isolation valve groups. Each auxiliary lifting mechanism is correspondingly configured with one isolation valve group. The corresponding auxiliary lifting mechanisms and isolation valve groups are connected in series. By activating different numbers of auxiliary lifting mechanisms and isolation valve groups, the operator can flexibly control the torque and speed output of the lifting hydraulic system to adapt to various working conditions. Therefore, this design can adapt the system to various working conditions through multiple individually controlled auxiliary lifting mechanisms and isolation valve groups, effectively improving the flexibility of system power control.

[0030] 5. In the control method of the gear and rack lifting hydraulic system based on an offshore platform according to the present invention, the operator needs to manually energize the brake control valve during operation. At this time, the brake control valve is connected, allowing hydraulic oil to enter the rodless chambers of each main brake and each auxiliary brake. The telescopic rods of the main brake and auxiliary brake extend, releasing the locking of the main lifting mechanism unit and the auxiliary lifting mechanism unit. When the system lifting is completed, the brake control valve is de-energized, and the main lifting mechanism unit and the auxiliary lifting mechanism unit are locked again. Therefore, this design can automatically lock the main lifting mechanism unit and the auxiliary lifting mechanism unit with the normally closed brake control valve, effectively improving system safety. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the structure of the present invention.

[0032] Figure 2 yes Figure 1 A schematic diagram of the structure of the intermediate gear.

[0033] Figure 3 This is a hydraulic schematic diagram of the present invention.

[0034] Figure 4 yes Figure 3 Hydraulic schematic diagram of a medium-sized hydraulic oil pump.

[0035] Figure 5 yes Figure 3 Hydraulic schematic diagram of the main lifting mechanism unit.

[0036] Figure 6 yes Figure 3 Hydraulic schematic diagram of the auxiliary lifting mechanism unit.

[0037] Figure 7 yes Figure 3 Hydraulic schematic diagram of the isolation valve assembly.

[0038] In the diagram: 1. Pile leg; 11. Rack; 2. Hydraulic pump; 21. Closed main pump; 22. Motor; 23. Control pump; 24. Built-in replenishing pump; 3. Lifting device; 4. Main lifting mechanism; 41. Main lifting mechanism unit; 42. Fixed displacement motor; 43. First lifting solenoid valve; 44. Second lifting solenoid valve; 45. First lifting relief valve; 46. Second lifting relief valve; 47. Main brake; 48. Gear; 5. Auxiliary lifting mechanism; 51. Auxiliary lifting mechanism unit; 52. Auxiliary fixed displacement motor; 53. First auxiliary lifting solenoid valve; 54. Second auxiliary lifting mechanism unit; 55. Auxiliary fixed displacement motor; 56. Second auxiliary lifting mechanism unit; 57. Main lifting mechanism unit; 58. Auxiliary lifting mechanism unit; 59. Auxiliary fixed displacement motor; 50. First auxiliary lifting solenoid valve; 51. Second auxiliary lifting mechanism unit; 52. Auxiliary fixed displacement motor; 52. First auxiliary lifting solenoid valve; 53. Second auxiliary lifting mechanism unit; 54. Main lifting mechanism unit; 55. Main lifting mechanism unit; 56. Main lifting mechanism unit; 57. Main lifting mechanism unit; 58. Main lifting mechanism unit; 59. Main lifting mechanism unit; 50. Main lifting mechanism unit; 51 ... Main lifting mechanism unit; 52. Main lifting mechanism unit; 53. Main lifting mechanism unit; 54. Main lifting mechanism unit; 5 54. Solenoid valve 54, First auxiliary lifting relief valve 55, Second auxiliary lifting relief valve 56, Auxiliary brake 57, Isolation valve group 6, First two-way cartridge valve 61, Second two-way cartridge valve 62, First hydraulic directional valve 63, Shuttle valve 64, Second hydraulic directional valve 65, Third two-way cartridge valve 66, First low-pressure shuttle valve 67, First check valve 68, Second check valve 69, Second low-pressure shuttle valve 70, Back pressure check valve 71, Hydraulic directional valve 72, Throttle valve 73, Isolation valve group control valve 7, Brake control valve 8. Detailed Implementation

[0039] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0040] See Figures 1 to 7A control method for a gear and rack lifting hydraulic system based on an offshore platform is disclosed. The lifting hydraulic system includes: multiple legs 1, multiple hydraulic pumps 2, and multiple lifting devices 3. The number of hydraulic pumps 2 is the same as the number of lifting devices 3. Each leg 1 is vertically fixed to the ground. Multiple racks 11 are vertically arranged on the sides of each leg 1, evenly distributed around its circumference. Each leg 1 is fitted with a lifting device 3. Each lifting device 3 is supplied with hydraulic oil by a hydraulic pump 2. Each lifting device 3 includes a main lifting mechanism 4, an auxiliary lifting mechanism 5, and an isolation valve group 6. The main lifting mechanism 4 includes multiple main lifting mechanism units 41, and the auxiliary lifting mechanism 5 includes multiple auxiliary lifting mechanism units 51 and an isolation valve group 6. The main lifting mechanism units 41 and auxiliary lifting mechanism units 51 have identical structures. The power output ends of the main lifting mechanism units 41 and auxiliary lifting mechanism units 51 are equipped with transmission devices for the racks 11. The gears 48 on the main lifting mechanism unit 41 and the auxiliary lifting mechanism unit 51 rotate synchronously. The first oil port of the hydraulic oil pump 2 is connected to the A chamber of each main lifting mechanism unit 41. The A1 port of the isolation valve group 6 is connected to the A chamber of each main lifting mechanism unit 41. The A2 port of the isolation valve group 6 is connected to the A chamber of each auxiliary lifting mechanism unit 51. The second oil port of the hydraulic oil pump 2 is connected to the B chamber of each main lifting mechanism unit 41. Port B1 of group 6 is connected to the B chamber of each main lifting mechanism unit 41. Port B2 of isolation valve group 6 is connected to the B chamber of each auxiliary lifting mechanism unit 51. The connection and disconnection between ports A1 and A2 of isolation valve group 6 are controlled by isolation valve group control valve 7. The connection and disconnection between ports B1 and B2 of isolation valve group 6 are controlled by isolation valve group control valve 7. Isolation valve group control valve 7 is a two-position three-position normally closed solenoid valve. The oil inlet of isolation valve group control valve 7 is connected to the control oil port of hydraulic oil pump 2.

[0041] The hydraulic pump 2 includes a closed main pump 21 and a motor 22. The closed main pump 21 is a hydraulic pump whose opening and rotation direction are controlled by a handle. The oil inlet of the closed main pump 21 is connected to the oil tank. The first oil outlet of the closed main pump 21 is connected to the first oil inlet of the main lifting mechanism 4 and the auxiliary lifting mechanism 5. The second oil outlet of the closed main pump 21 is connected to the second oil inlet of the main lifting mechanism 4 and the auxiliary lifting mechanism 5. The power output end of the motor 22 is fixedly connected to the main shaft of the closed main pump 21.

[0042] The number of main lifting mechanism units 41 provided within the main lifting mechanism 4 is an integer multiple of the number of racks 11 provided on the pile leg 1. The main lifting mechanism units 41 within the main lifting mechanism 4 are divided into multiple groups, with the number of main lifting mechanism units 41 in each group being the same as the number of racks 11 provided on the pile leg 1. Each main lifting mechanism unit 41 includes a fixed displacement motor 42, a first lifting solenoid valve 43, a second lifting solenoid valve 44, a first lifting overflow valve 45, and a second lifting overflow valve 46. The first lifting solenoid valve 43 and the second lifting solenoid valve 44 are both two-position, two-position normally closed solenoid valves. The oil inlet of the first lifting solenoid valve 43 is connected to the first oil outlet of the closed main pump 21. The oil outlet of the solenoid valve 43 is connected to the A chamber of the fixed displacement motor 42; the oil inlet of the second lifting solenoid valve 44 is connected to the second oil outlet of the closed main pump 21; the oil outlet of the second lifting solenoid valve 44 is connected to the B chamber of the fixed displacement motor 42; the oil discharge port of the fixed displacement motor 42 is connected to the oil tank; the oil inlet of the first lifting overflow valve 45 is connected to the oil outlet of the first lifting solenoid valve 43; the oil outlet of the first lifting overflow valve 45 is connected to the oil outlet of the second lifting solenoid valve 44; the oil inlet of the second lifting overflow valve 46 is connected to the oil outlet of the second lifting solenoid valve 44; and the oil outlet of the second lifting overflow valve 46 is connected to the oil outlet of the first lifting solenoid valve 43.

[0043] The number of auxiliary lifting mechanism units 51 provided within the auxiliary lifting mechanism 5 is an integer multiple of the number of racks 11 provided on the pile leg 1. The auxiliary lifting mechanism units 51 within the auxiliary lifting mechanism 5 are divided into multiple groups, with the number of auxiliary lifting mechanism units 51 in each group being the same as the number of racks 11 provided on the pile leg 1. Each auxiliary lifting mechanism unit 51 includes an auxiliary quantitative motor 52, a first auxiliary lifting solenoid valve 53, a second auxiliary lifting solenoid valve 54, a first auxiliary lifting overflow valve 55, and a second auxiliary lifting overflow valve 56. The first auxiliary lifting solenoid valve 53 and the second auxiliary lifting solenoid valve 54 are both two-position, two-position normally closed solenoid valves. The oil inlet of the first auxiliary lifting solenoid valve 53 is connected to the first oil outlet of the closed main pump 21. The oil outlet of valve 53 is connected to chamber A of auxiliary quantitative motor 52; the oil inlet of the second auxiliary lifting solenoid valve 54 is connected to the second oil outlet of closed main pump 21; the oil outlet of the second auxiliary lifting solenoid valve 54 is connected to chamber B of auxiliary quantitative motor 52; the oil discharge port of auxiliary quantitative motor 52 is connected to oil tank; the oil inlet of the first auxiliary lifting overflow valve 55 is connected to the oil outlet of the first auxiliary lifting solenoid valve 53; the oil outlet of the first auxiliary lifting overflow valve 55 is connected to the oil outlet of the second auxiliary lifting solenoid valve 54; the oil inlet of the second auxiliary lifting overflow valve 56 is connected to the oil outlet of the second auxiliary lifting solenoid valve 54; and the oil outlet of the second auxiliary lifting overflow valve 56 is connected to the oil outlet of the first auxiliary lifting solenoid valve 53.

[0044] The isolation valve group 6 includes a first two-way cartridge valve 61, a second two-way cartridge valve 62, a first hydraulically controlled directional valve 63, a shuttle valve 64, a second hydraulically controlled directional valve 65, a third two-way cartridge valve 66, a first low-pressure shuttle valve 67, a first check valve 68, a second check valve 69, a second low-pressure shuttle valve 70, a back pressure check valve 71, a hydraulically controlled directional valve 72, and a throttle valve 73. The first two-way cartridge valve 61 and the second two-way cartridge valve 62 are normally open cartridge valves. The inlet of the first two-way cartridge valve 61 is connected to chamber A of the fixed displacement motor 42 in the main lifting mechanism 4, and the outlet of the first two-way cartridge valve 61 is connected to chamber A of the fixed displacement motor 42 in the auxiliary lifting mechanism 5. The inlet of the second two-way cartridge valve 62 is connected to the fixed displacement motor 42 in the main lifting mechanism 4. The B chamber of motor 42 is connected. The oil outlet of the second two-way cartridge valve 62 is connected to the oil inlet of the B chamber of the fixed displacement motor 42 in the auxiliary lifting mechanism 5. The control ports of the first two-way cartridge valve 61 and the second two-way cartridge valve 62 are connected to the oil outlet of the first hydraulic directional valve 63. The control port of the first hydraulic directional valve 63 is connected to the oil outlet of the isolation valve group control valve 7. The unloading port of the first hydraulic directional valve 63 is connected to the oil tank. The oil inlet of the first hydraulic directional valve 63 is connected to the oil outlet of the shuttle valve 64. The first oil inlet of the shuttle valve 64 is connected to the A chamber of the fixed displacement motor 42 in the main lifting mechanism 4. The second oil inlet of the shuttle valve 64 is connected to the B chamber of the fixed displacement motor 42 in the main lifting mechanism 4. The oil outlet of valve 64 is connected to the oil inlet of the second hydraulic directional valve 65. The control oil port of the second hydraulic directional valve 65 is connected to the oil outlet of the isolation valve group control valve 7. The oil outlet of the second hydraulic directional valve 65 is connected to the control oil port of the third two-way cartridge valve 66. The oil outlet of the second hydraulic directional valve 65 is connected to the oil tank. The first oil outlet of the third two-way cartridge valve 66 is connected to chamber A of the auxiliary lifting mechanism 5. The second oil outlet of the third two-way cartridge valve 66 is connected to chamber B of the auxiliary lifting mechanism 5. The first oil inlet of the first low-pressure shuttle valve 67 is connected to chamber A of the fixed displacement motor 42 in the main lifting mechanism 4. The second oil inlet of the first low-pressure shuttle valve 67 is connected to chamber B of the fixed displacement motor 42 in the main lifting mechanism 4. The chambers are connected. The oil outlet of the first low-pressure shuttle valve 67 is connected to the oil inlet of the first one-way valve 68 and the second one-way valve 69. The oil outlet of the first one-way valve 68 is connected to chamber A of the auxiliary lifting mechanism 5. The second one-way valve 69 is connected to chamber B of the auxiliary lifting mechanism 5. The first oil inlet of the second low-pressure shuttle valve 70 is connected to the oil outlet of the first two-way cartridge valve 61. The second oil inlet of the second low-pressure shuttle valve 70 is connected to the oil outlet of the second two-way cartridge valve 62. The oil outlet of the second low-pressure shuttle valve 70 is connected to the oil inlet of the throttle valve 73. The oil outlet of the throttle valve 73 is connected to the oil inlet of the hydraulically controlled directional valve 72. The control port of the hydraulically controlled directional valve 72 is connected to the oil outlet of the isolation valve group control valve 7.The oil outlet of the hydraulically controlled directional valve 72 is connected to the oil inlet of the back pressure check valve 71, and the oil outlet of the back pressure check valve 71 is connected to the oil tank.

[0045] The hydraulic oil pump 2 also includes a control pump 23. The main shaft of the control pump 23 is fixedly connected to the power output shaft of the motor 22. The oil inlet of the control pump 23 is connected to the oil tank. The oil outlet of the control pump 23 is connected to the oil inlet of the isolation valve group control valve 7. The oil outlet of the isolation valve group control valve 7 is connected to the oil tank.

[0046] The lifting hydraulic system also includes a brake control valve 8, which is a two-position three-position normally closed solenoid valve. The main lifting mechanism 4 also includes a main brake 47, and the auxiliary lifting mechanism 5 also includes an auxiliary brake 57. The oil inlet of the brake control valve 8 is connected to the oil outlet of the control pump 23. The working oil port of the brake control valve 8 is connected to the rodless chamber of each main brake 47 and each auxiliary brake 57. The oil outlet of the brake control valve 8 is connected to the oil tank.

[0047] The hydraulic oil pump 2 also includes a built-in replenishing pump 24, the oil inlet of which is connected to the oil tank, and the oil outlet of which is connected to the oil inlet of the closed main pump 21.

[0048] The lifting device 3 includes a main lifting mechanism 4, multiple auxiliary lifting mechanisms 5, and multiple isolation valve groups 6. The number of auxiliary lifting mechanisms 5 is the same as the number of isolation valve groups 6. Each auxiliary lifting mechanism 5 is correspondingly arranged with one isolation valve group 6 to form an auxiliary lifting module. The auxiliary lifting modules formed by each group of auxiliary lifting mechanisms 5 and isolation valve groups 6 are connected in series end to end. Each auxiliary lifting mechanism 5 has its A chamber connected to its corresponding isolation valve group 6's A2 port, and each auxiliary lifting mechanism 5 has its B chamber connected to its corresponding isolation valve group 6's B2 port. One isolation valve group 6's A1 port is connected to each main lifting mechanism unit 41's A chamber, and another isolation valve group 6's B1 port is connected to each main lifting mechanism unit 41's B chamber. The remaining isolation valve groups 6 have their A1 ports sequentially connected to their corresponding auxiliary lifting mechanism units 51's A chamber, and their B1 ports sequentially connected to their corresponding auxiliary lifting mechanism units 51's A chamber. The lifting hydraulic system includes multiple isolation valve group control valves 7, the number of which is the same as the number of isolation valve groups 6. Each isolation valve group control valve 7 is correspondingly set to one isolation valve group 6. The connection / disconnection between the A1 and A2 ports of each isolation valve group 6 is controlled by its corresponding isolation valve group control valve 7.

[0049] A control method for a gear and rack lifting hydraulic system based on an offshore platform, the control method comprising the following steps:

[0050] Step 1: Offshore platform erection. Operators navigate the vessel to transport the offshore platform to the work area. Once the platform arrives, operators activate all motors 22 on the platform, simultaneously energizing the brake control valve 8, the first lifting solenoid valve 43, and the second lifting solenoid valve 44. The motors 22 drive the corresponding closed-loop main pumps 21 to begin operation. At this time, the operator drives the control handle of the closed-loop main pump 21, opening its first port. The closed-loop main pump 21 then delivers hydraulic oil to the A chamber of each main lifting mechanism unit 41 and the rodless chamber of each main brake 47. At this time, the extension rod of the main brake 47 extends, releasing the lock of each main lifting mechanism unit 41. The gear 48 of each main lifting mechanism unit 41 rotates, driving the pile leg 1 to move downward. When the bottom of a certain pile leg 1 contacts the seabed and is limited by the seabed, the force between the pile leg 1 and the offshore platform causes the offshore platform to rise. At this time, the motor 22 corresponding to the pile leg 1 is turned off. When all motors 22 are turned off, the offshore platform piling step is completed. Depending on the offshore platform working conditions, the second step offshore platform rising step, the third step offshore platform lowering step, or the fourth step offshore platform piling step can be entered.

[0051] Step 2: Elevation of the offshore platform. When the offshore platform needs to be elevated, the operator activates each motor 22 and each built-in oil replenishment pump 24. Simultaneously, the operator energizes the isolation valve group control valve 7, brake control valve 8, first lifting solenoid valve 43, second lifting solenoid valve 44, first auxiliary lifting solenoid valve 53, and second auxiliary lifting solenoid valve 54. At this time, the A1 and A2 ports and the B1 and B2 ports of the isolation valve group 6 are connected. The operator then drives the control handle of the closed main pump 21, opening the first oil port of the closed main pump 21. The closed main pump 21 delivers hydraulic oil to each main lifting mechanism. In the A chamber of the main lifting unit 41, the A chamber of each auxiliary lifting mechanism unit 51, the rodless chamber of each main brake 47 and each auxiliary brake 57, the telescopic rods of the main brake 47 and the auxiliary brake 57 extend, releasing the locks of each main lifting mechanism unit 41 and each auxiliary lifting mechanism unit 51. The gears 48 in each main lifting mechanism unit 41 and each auxiliary lifting mechanism unit 51 rotate, driving the offshore platform to move upward. When the offshore platform reaches the designated height, the operator shuts off all motors 22 and the built-in oil pump 24. At this time, the offshore platform lifting step is completed.

[0052] Step 3: Lowering the offshore platform. When the offshore platform needs to be lowered, the operator activates each motor 22 and each built-in oil replenishment pump 24. Simultaneously, the operator energizes the isolation valve group control valve 7, brake control valve 8, first lifting solenoid valve 43, second lifting solenoid valve 44, first auxiliary lifting solenoid valve 53, and second auxiliary lifting solenoid valve 54. At this time, the A1 and A2 ports and the B1 and B2 ports of the isolation valve group 6 are connected. The operator then drives the control handle of the closed main pump 21, opening the second oil port of the closed main pump 21. The closed main pump 21 delivers hydraulic oil to each main lifting mechanism. In the B chamber of the main lifting unit 41, the B chamber of each auxiliary lifting mechanism unit 51, the rodless chamber of each main brake 47 and each auxiliary brake 57, the telescopic rods of the main brake 47 and the auxiliary brake 57 extend, releasing the locks of each main lifting mechanism unit 41 and each auxiliary lifting mechanism unit 51. The gears 48 in each main lifting mechanism unit 41 and each auxiliary lifting mechanism unit 51 rotate, driving the offshore platform to move downward. When the offshore platform reaches the designated height, the operator shuts off all motors 22 and the built-in oil pump 24. At this time, the descent of the offshore platform is completed.

[0053] Step 4: Offshore Platform Pile Lifting. When the pile leg 1 needs to be raised, the operator maneuvers the vessel directly beneath the offshore platform and activates all motors 22 and all built-in oil replenishment pumps 24. Simultaneously, the isolation valve group control valve 7, brake control valve 8, first lifting solenoid valve 43, second lifting solenoid valve 44, first auxiliary lifting solenoid valve 53, and second auxiliary lifting solenoid valve 54 are energized. At this time, the A1 and A2 ports and the B1 and B2 ports of the isolation valve group 6 are connected. At the same time, the motor 22 drives the corresponding closed main pump 21 to start working. The operator then drives the control handle of the closed main pump 21 to open the second oil port of the closed main pump 21. The closed main pump 21 delivers hydraulic oil to the B chamber of each main lifting mechanism unit 41, the B chamber of each auxiliary lifting mechanism unit 51, and the main... In the rodless chambers of brake 47 and each auxiliary brake 57, the telescopic rods of the main brake 47 and auxiliary brake 57 extend, releasing the locking of each main lifting mechanism unit 41 and each auxiliary lifting mechanism unit 51. The gears 48 in each main lifting mechanism unit 41 and each auxiliary lifting mechanism unit 51 rotate, driving the offshore platform downward. When the bottom of the offshore platform is at the limit with the top of the ship, the operator controls the disconnection between ports A1 and A2 and ports B1 and B2 of the isolation valve group 6 through the isolation valve group control valve 7. At this time, the gears 48 in each main lifting mechanism unit 41 rotate. The force between each leg 1 and the offshore platform causes all legs 1 to move upward. When all legs 1 have risen to the designated height, the offshore platform piling step is completed.

[0054] The principle of this invention is explained as follows:

[0055] In this invention, the low-pressure oil in port A1 or port B1 of the isolation valve group 6 passes through the first low-pressure shuttle valve 67 and overcomes the back pressure of the first check valve 68 or the second check valve 69, and inputs the oil into the low-pressure chamber of the auxiliary lifting mechanism 5. When the hydraulic system heats up significantly, the hot oil on the low-pressure side is returned through the second low-pressure shuttle valve 70, passes through the throttle valve 73, opens the hydraulic control directional valve 72, and overcomes the back pressure check valve 71 to return to the oil tank, thereby realizing hot and cold oil replacement.

[0056] In this invention, not only can one auxiliary lifting mechanism 5 be controlled by one isolation valve group 6, but multiple auxiliary lifting mechanisms 5 can also be controlled by one isolation valve group 6.

[0057] Example 1:

[0058] A gear and rack lifting hydraulic system for an offshore platform includes: multiple legs 1, multiple hydraulic pumps 2, and multiple lifting devices 3. The number of hydraulic pumps 2 is the same as the number of lifting devices 3. The multiple legs 1 are all fixedly installed vertically on the ground. Multiple racks 11 are arranged vertically on the side of each leg 1. The racks 11 are evenly arranged around the circumference of the leg 1. Each leg 1 is fitted with a lifting device 3. The multiple lifting devices 3 are supplied with hydraulic oil by a hydraulic pump 2. Each lifting device 3 includes a main lifting mechanism 4, an auxiliary lifting mechanism 5, and an isolation valve group 6. The main lifting mechanism 4 includes multiple main lifting mechanism units 4. 1. The auxiliary lifting mechanism 5 includes multiple auxiliary lifting mechanism units 51 and an isolation valve group 6. The main lifting mechanism unit 41 and the auxiliary lifting mechanism unit 51 have the same structure. Gears 48 that mesh with the rack and pinion 11 are provided on the power output ends of the main lifting mechanism unit 41 and the auxiliary lifting mechanism unit 51. The gears 48 on the main lifting mechanism unit 41 and the auxiliary lifting mechanism unit 51 rotate synchronously. The first oil port of the hydraulic oil pump 2 is connected to the A chamber of each main lifting mechanism unit 41. The A1 port of the isolation valve group 6 is connected to the A chamber of each main lifting mechanism unit 41. The A2 port of the isolation valve group 6 is connected to the A chamber of each auxiliary lifting mechanism unit 51. The hydraulic oil... The second oil port of pump 2 is connected to the B chamber of each main lifting mechanism unit 41. The B1 port of the isolation valve group 6 is connected to the B chamber of each main lifting mechanism unit 41. The B2 port of the isolation valve group 6 is connected to the B chamber of each auxiliary lifting mechanism unit 51. The connection and disconnection between the A1 and A2 ports of the isolation valve group 6 are controlled by the isolation valve group control valve 7. The connection and disconnection between the B1 and B2 ports of the isolation valve group 6 are also controlled by the isolation valve group control valve 7. The isolation valve group control valve 7 is a two-position three-position normally closed solenoid valve. The oil inlet of the isolation valve group control valve 7 is connected to the control oil port of the hydraulic oil pump 2. The hydraulic oil pump 2 includes a closed main pump 21 and a motor 22. The closed main pump 21 is controlled by a handle. The hydraulic pump controls the opening degree and rotation direction. The inlet of the closed-loop main pump 21 is connected to the oil tank. The first outlet of the closed-loop main pump 21 is connected to the first inlet of the main lifting mechanism 4 and the auxiliary lifting mechanism 5. The second outlet of the closed-loop main pump 21 is connected to the second inlet of the main lifting mechanism 4 and the auxiliary lifting mechanism 5. The power output end of the motor 22 is fixedly connected to the main shaft of the closed-loop main pump 21. The number of main lifting mechanism units 41 provided in the main lifting mechanism 4 is an integer multiple of the number of racks 11 provided on the pile leg 1. The main lifting mechanism units 41 provided in the main lifting mechanism 4 are divided into multiple groups, and the number of main lifting mechanism units 41 in each group is the same as the number of racks 11 provided on the pile leg 1.The main lifting mechanism unit 41 includes a fixed displacement motor 42, a first lifting solenoid valve 43, a second lifting solenoid valve 44, a first lifting relief valve 45, and a second lifting relief valve 46. Both the first lifting solenoid valve 43 and the second lifting solenoid valve 44 are two-position, normally closed solenoid valves. The oil inlet of the first lifting solenoid valve 43 is connected to the first oil outlet of the closed-loop main pump 21, and the oil outlet of the first lifting solenoid valve 43 is connected to chamber A of the fixed displacement motor 42. The oil inlet of the second lifting solenoid valve 44 is connected to the second oil outlet of the closed-loop main pump 21, and the oil outlet of the second lifting solenoid valve 44 is connected to chamber B of the fixed displacement motor 42. The oil discharge port of the quantitative motor 42 is connected to the oil tank; the oil inlet of the first lifting overflow valve 45 is connected to the oil outlet of the first lifting solenoid valve 43; the oil outlet of the first lifting overflow valve 45 is connected to the oil outlet of the second lifting solenoid valve 44; the oil inlet of the second lifting overflow valve 46 is connected to the oil outlet of the second lifting solenoid valve 44; and the oil outlet of the second lifting overflow valve 46 is connected to the oil outlet of the first lifting solenoid valve 43. The number of auxiliary lifting mechanism units 51 provided in the auxiliary lifting mechanism 5 is an integer multiple of the number of racks 11 provided on the pile leg 1. The auxiliary lifting mechanism unit 51 is divided into multiple groups, and the number of auxiliary lifting mechanism units 51 in each group is the same as the number of racks 11 set on the pile leg 1. The auxiliary lifting mechanism unit 51 includes an auxiliary quantitative motor 52, a first auxiliary lifting solenoid valve 53, a second auxiliary lifting solenoid valve 54, a first auxiliary lifting overflow valve 55, and a second auxiliary lifting overflow valve 56. The first auxiliary lifting solenoid valve 53 and the second auxiliary lifting solenoid valve 54 are both two-position normally closed solenoid valves. The oil inlet of the first auxiliary lifting solenoid valve 53 is connected to the first oil outlet of the closed main pump 21, and the oil outlet of the first auxiliary lifting solenoid valve 53 is connected to the auxiliary... The A chamber of the fixed displacement motor 52 is connected; the inlet of the second auxiliary lifting solenoid valve 54 is connected to the second outlet of the closed main pump 21; the outlet of the second auxiliary lifting solenoid valve 54 is connected to the B chamber of the auxiliary fixed displacement motor 52; the unloading port of the auxiliary fixed displacement motor 52 is connected to the oil tank; the inlet of the first auxiliary lifting overflow valve 55 is connected to the outlet of the first auxiliary lifting solenoid valve 53; the outlet of the first auxiliary lifting overflow valve 55 is connected to the outlet of the second auxiliary lifting solenoid valve 54; and the inlet of the second auxiliary lifting overflow valve 56 is connected to the outlet of the second auxiliary lifting solenoid valve 54.The oil outlet of the second auxiliary lifting overflow valve 56 is connected to the oil outlet of the first auxiliary lifting solenoid valve 53; the isolation valve group 6 includes a first two-way cartridge valve 61, a second two-way cartridge valve 62, a first hydraulically controlled directional valve 63, a shuttle valve 64, a second hydraulically controlled directional valve 65, a third two-way cartridge valve 66, a first low-pressure shuttle valve 67, a first check valve 68, a second check valve 69, a second low-pressure shuttle valve 70, a back pressure check valve 71, a hydraulically controlled directional valve 72, and a throttle valve 73. The first two-way cartridge valve 61 and the second two-way cartridge valve 62 are normally open cartridge valves. The oil inlet of the first two-way cartridge valve 61 is connected to the A chamber of the fixed displacement motor 42 in the main lifting mechanism 4, and the oil outlet of the first two-way cartridge valve 61 is connected to the fixed displacement motor 42 in the auxiliary lifting mechanism 5. The first two-way cartridge valve 61 and the second two-way cartridge valve 62 are connected to the A chamber of the main lifting mechanism 4. The oil inlet of the second two-way cartridge valve 62 is connected to the B chamber of the fixed displacement motor 42 in the main lifting mechanism 4. The oil outlet of the second two-way cartridge valve 62 is connected to the oil inlet of the B chamber of the fixed displacement motor 42 in the auxiliary lifting mechanism 5. The control ports of the first two-way cartridge valve 61 and the second two-way cartridge valve 62 are connected to the oil outlet of the first hydraulic directional valve 63. The control port of the first hydraulic directional valve 63 is connected to the oil outlet of the isolation valve group control valve 7. The unloading port of the first hydraulic directional valve 63 is connected to the oil tank. The oil inlet of the first hydraulic directional valve 63 is connected to the oil outlet of the shuttle valve 64. The first oil inlet of the shuttle valve 64 is connected to the A chamber of the fixed displacement motor 42 in the main lifting mechanism 4. The second oil inlet of shuttle valve 64 is connected to chamber B of the fixed displacement motor 42 in the main lifting mechanism 4. The oil outlet of shuttle valve 64 is connected to the oil inlet of the second hydraulic directional valve 65. The control oil port of the second hydraulic directional valve 65 is connected to the oil outlet of the isolation valve group control valve 7. The oil outlet of the second hydraulic directional valve 65 is connected to the control oil port of the third two-way cartridge valve 66. The oil outlet of the second hydraulic directional valve 65 is connected to the oil tank. The first oil outlet of the third two-way cartridge valve 66 is connected to chamber A of the auxiliary lifting mechanism 5. The second oil outlet of the third two-way cartridge valve 66 is connected to chamber B of the auxiliary lifting mechanism 5. The first oil inlet of the first low-pressure shuttle valve 67 is connected to chamber A of the fixed displacement motor 42 in the main lifting mechanism 4. The second inlet of the first low-pressure shuttle valve 67 is connected to chamber B of the fixed displacement motor 42 in the main lifting mechanism 4. The outlet of the first low-pressure shuttle valve 67 is connected to the inlets of the first one-way valve 68 and the second one-way valve 69. The outlet of the first one-way valve 68 is connected to chamber A of the auxiliary lifting mechanism 5. The second one-way valve 69 is connected to chamber B of the auxiliary lifting mechanism 5. The first inlet of the second low-pressure shuttle valve 70 is connected to the outlet of the first two-way cartridge valve 61. The second inlet of the second low-pressure shuttle valve 70 is connected to the outlet of the second two-way cartridge valve 62. The outlet of the second low-pressure shuttle valve 70 is connected to the inlet of the throttle valve 73. The outlet of the throttle valve 73 is connected to the inlet of the hydraulic directional valve 72.The control port of the hydraulic directional valve 72 is connected to the outlet of the isolation valve group control valve 7, and the outlet of the hydraulic directional valve 72 is connected to the inlet of the back pressure check valve 71. The outlet of the back pressure check valve 71 is connected to the oil tank. The hydraulic pump 2 also includes a control pump 23. The main shaft of the control pump 23 is fixedly connected to the power output shaft of the motor 22. The inlet of the control pump 23 is connected to the oil tank, and the outlet of the control pump 23 is connected to the inlet of the isolation valve group control valve 7. The isolation valve group... The discharge port of control valve 7 is connected to the oil tank; the lifting hydraulic system also includes a brake control valve 8, which is a two-position, three-position normally closed solenoid valve; the main lifting mechanism 4 also includes a main brake 47; the auxiliary lifting mechanism 5 also includes an auxiliary brake 57; the inlet of brake control valve 8 is connected to the outlet of control pump 23; the working port of brake control valve 8 is connected to the rodless chamber of each main brake 47 and each auxiliary brake 57; and the discharge port of brake control valve 8 is connected to the oil tank.

[0059] A control method for a gear and rack lifting hydraulic system based on an offshore platform, the control method comprising the following steps:

[0060] Step 1: Offshore platform erection. Operators navigate the vessel to transport the offshore platform to the work area. Once the platform arrives, operators activate all motors 22 on the platform, simultaneously energizing the brake control valve 8, the first lifting solenoid valve 43, and the second lifting solenoid valve 44. The motors 22 drive the corresponding closed-loop main pumps 21 to begin operation. At this time, the operator drives the control handle of the closed-loop main pump 21, opening its first port. The closed-loop main pump 21 then delivers hydraulic oil to the A chamber of each main lifting mechanism unit 41 and the rodless chamber of each main brake 47. At this time, the extension rod of the main brake 47 extends, releasing the lock of each main lifting mechanism unit 41. The gear 48 of each main lifting mechanism unit 41 rotates, driving the pile leg 1 to move downward. When the bottom of a certain pile leg 1 contacts the seabed and is limited by the seabed, the force between the pile leg 1 and the offshore platform causes the offshore platform to rise. At this time, the motor 22 corresponding to the pile leg 1 is turned off. When all motors 22 are turned off, the offshore platform piling step is completed. Depending on the offshore platform working conditions, the second step offshore platform rising step, the third step offshore platform lowering step, or the fourth step offshore platform piling step can be entered.

[0061] Step 2: Elevation of the offshore platform. When the offshore platform needs to be elevated, the operator activates each motor 22 and each built-in oil replenishment pump 24. Simultaneously, the operator energizes the isolation valve group control valve 7, brake control valve 8, first lifting solenoid valve 43, second lifting solenoid valve 44, first auxiliary lifting solenoid valve 53, and second auxiliary lifting solenoid valve 54. At this time, the A1 and A2 ports and the B1 and B2 ports of the isolation valve group 6 are connected. The operator then drives the control handle of the closed main pump 21, opening the first oil port of the closed main pump 21. The closed main pump 21 delivers hydraulic oil to each main lifting mechanism. In the A chamber of the main lifting unit 41, the A chamber of each auxiliary lifting mechanism unit 51, the rodless chamber of each main brake 47 and each auxiliary brake 57, the telescopic rods of the main brake 47 and the auxiliary brake 57 extend, releasing the locks of each main lifting mechanism unit 41 and each auxiliary lifting mechanism unit 51. The gears 48 in each main lifting mechanism unit 41 and each auxiliary lifting mechanism unit 51 rotate, driving the offshore platform to move upward. When the offshore platform reaches the designated height, the operator shuts off all motors 22 and the built-in oil pump 24. At this time, the offshore platform lifting step is completed.

[0062] Step 3: Lowering the offshore platform. When the offshore platform needs to be lowered, the operator activates each motor 22 and each built-in oil replenishment pump 24. Simultaneously, the operator energizes the isolation valve group control valve 7, brake control valve 8, first lifting solenoid valve 43, second lifting solenoid valve 44, first auxiliary lifting solenoid valve 53, and second auxiliary lifting solenoid valve 54. At this time, the A1 and A2 ports and the B1 and B2 ports of the isolation valve group 6 are connected. The operator then drives the control handle of the closed main pump 21, opening the second oil port of the closed main pump 21. The closed main pump 21 delivers hydraulic oil to each main lifting mechanism. In the B chamber of the main lifting unit 41, the B chamber of each auxiliary lifting mechanism unit 51, the rodless chamber of each main brake 47 and each auxiliary brake 57, the telescopic rods of the main brake 47 and the auxiliary brake 57 extend, releasing the locks of each main lifting mechanism unit 41 and each auxiliary lifting mechanism unit 51. The gears 48 in each main lifting mechanism unit 41 and each auxiliary lifting mechanism unit 51 rotate, driving the offshore platform to move downward. When the offshore platform reaches the designated height, the operator shuts off all motors 22 and the built-in oil pump 24. At this time, the descent of the offshore platform is completed.

[0063] Step 4: Offshore Platform Pile Lifting. When the pile leg 1 needs to be raised, the operator maneuvers the vessel directly beneath the offshore platform and activates all motors 22 and all built-in oil replenishment pumps 24. Simultaneously, the isolation valve group control valve 7, brake control valve 8, first lifting solenoid valve 43, second lifting solenoid valve 44, first auxiliary lifting solenoid valve 53, and second auxiliary lifting solenoid valve 54 are energized. At this time, the A1 and A2 ports and the B1 and B2 ports of the isolation valve group 6 are connected. At the same time, the motor 22 drives the corresponding closed main pump 21 to start working. The operator then drives the control handle of the closed main pump 21 to open the second oil port of the closed main pump 21. The closed main pump 21 delivers hydraulic oil to the B chamber of each main lifting mechanism unit 41, the B chamber of each auxiliary lifting mechanism unit 51, and the main... In the rodless chambers of brake 47 and each auxiliary brake 57, the telescopic rods of the main brake 47 and auxiliary brake 57 extend, releasing the locking of each main lifting mechanism unit 41 and each auxiliary lifting mechanism unit 51. The gears 48 in each main lifting mechanism unit 41 and each auxiliary lifting mechanism unit 51 rotate, driving the offshore platform downward. When the bottom of the offshore platform is at the limit with the top of the ship, the operator controls the disconnection between ports A1 and A2 and ports B1 and B2 of the isolation valve group 6 through the isolation valve group control valve 7. At this time, the gears 48 in each main lifting mechanism unit 41 rotate. The force between each leg 1 and the offshore platform causes all legs 1 to move upward. When all legs 1 have risen to the designated height, the offshore platform piling step is completed.

[0064] Example 2:

[0065] Example 2 is basically the same as Example 1, except that:

[0066] The lifting device 3 includes a main lifting mechanism 4, multiple auxiliary lifting mechanisms 5, and multiple isolation valve groups 6. The number of auxiliary lifting mechanisms 5 is the same as the number of isolation valve groups 6. Each auxiliary lifting mechanism 5 is correspondingly arranged with one isolation valve group 6 to form an auxiliary lifting module. The auxiliary lifting modules formed by each group of auxiliary lifting mechanisms 5 and isolation valve groups 6 are connected in series end to end. Each auxiliary lifting mechanism 5 has its A chamber connected to its corresponding isolation valve group 6's A2 port, and each auxiliary lifting mechanism 5 has its B chamber connected to its corresponding isolation valve group 6's B2 port. One isolation valve group 6's A1 port is connected to each main lifting mechanism unit 41's A chamber, and another isolation valve group 6's B1 port is connected to each main lifting mechanism unit 41's B chamber. The remaining isolation valve groups 6 have their A1 ports sequentially connected to their corresponding auxiliary lifting mechanism units 51's A chamber, and their B1 ports sequentially connected to their corresponding auxiliary lifting mechanism units 51's A chamber. The lifting hydraulic system includes multiple isolation valve group control valves 7, the number of which is the same as the number of isolation valve groups 6. Each isolation valve group control valve 7 is correspondingly set to one isolation valve group 6. The connection / disconnection between the A1 and A2 ports of each isolation valve group 6 is controlled by its corresponding isolation valve group control valve 7.

[0067] Example 3:

[0068] Example 3 is basically the same as Example 2, except that:

[0069] The hydraulic oil pump 2 also includes a built-in replenishing pump 24, the oil inlet of which is connected to the oil tank, and the oil outlet of which is connected to the oil inlet of the closed main pump 21.

[0070] The above description is only a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. Any equivalent modifications or changes made by those skilled in the art based on the content disclosed in the present invention should be included within the scope of protection set forth in the claims.

Claims

1. A gear and rack lifting hydraulic system based on an offshore platform, characterized in that: The lifting hydraulic system includes: multiple pile legs (1), multiple hydraulic oil pumps (2) and multiple lifting devices (3). The number of hydraulic oil pumps (2) is the same as the number of lifting devices (3). The multiple pile legs (1) are all fixedly installed on the ground in a vertical direction. Multiple racks (11) are provided on the side of the pile leg (1) in a vertical direction. The multiple racks (11) are evenly arranged in the circumferential direction of the pile leg (1). Each pile leg (1) is fitted with a lifting device (3). The multiple lifting devices (3) are supplied with hydraulic oil by a hydraulic oil pump (2). The lifting device (3) includes a main lifting mechanism (4) and an auxiliary lifting mechanism (5). The main lifting mechanism (4) includes multiple main lifting mechanism units (41), and the auxiliary lifting mechanism (5) includes multiple auxiliary lifting mechanism units (51) and an isolation valve group (6). The main lifting mechanism units (41) and the auxiliary lifting mechanism units (51) have the same structure. The power output ends of the main lifting mechanism units (41) and the auxiliary lifting mechanism units (51) are equipped with gears (48) that are driven and cooperate with the rack (11). The gears (48) on the lifting mechanism unit (51) rotate synchronously. The first port of the hydraulic oil pump (2) is connected to the A chamber of each main lifting mechanism unit (41). The A1 port of the isolation valve group (6) is connected to the A chamber of each main lifting mechanism unit (41). The A2 port of the isolation valve group (6) is connected to the A chamber of each auxiliary lifting mechanism unit (51). The second port of the hydraulic oil pump (2) is connected to the B chamber of each main lifting mechanism unit (41). The B1 port of the isolation valve group (6) is connected to the B chamber of each main lifting mechanism unit (51). The B chamber of the lifting mechanism unit (41) is connected, and the B2 port of the isolation valve group (6) is connected to the B chamber of each auxiliary lifting mechanism unit (51). The connection and disconnection between the A1 port and the A2 port of the isolation valve group (6) is controlled by the isolation valve group control valve (7). The connection and disconnection between the B1 port and the B2 port of the isolation valve group (6) is controlled by the isolation valve group control valve (7). The isolation valve group control valve (7) is a two-position three-position normally closed solenoid valve. The oil inlet of the isolation valve group control valve (7) is connected to the control oil port of the hydraulic oil pump (2). The hydraulic pump (2) includes a closed main pump (21) and a motor (22). The closed main pump (21) is a hydraulic pump whose opening and rotation direction are controlled by a handle. The oil inlet of the closed main pump (21) is connected to the oil tank. The first oil outlet of the closed main pump (21) is connected to the first oil inlet of the main lifting mechanism (4) and the auxiliary lifting mechanism (5). The second oil outlet of the closed main pump (21) is connected to the second oil inlet of the main lifting mechanism (4) and the auxiliary lifting mechanism (5). The power output end of the motor (22) is fixedly connected to the main shaft of the closed main pump (21). The hydraulic oil pump (2) also includes a built-in replenishing pump (24), the oil inlet of which is connected to the oil tank, and the oil outlet of which is connected to the oil inlet of the closed main pump (21). The number of main lifting mechanism units (41) provided in the main lifting mechanism (4) is an integer multiple of the number of racks (11) provided on the pile leg (1). The main lifting mechanism units (41) provided in the main lifting mechanism (4) are divided into multiple groups, and the number of main lifting mechanism units (41) in each group is the same as the number of racks (11) provided on the pile leg (1). The number of auxiliary lifting mechanism units (51) provided in the auxiliary lifting mechanism (5) is an integer multiple of the number of racks (11) provided on the pile leg (1). The auxiliary lifting mechanism units (51) provided in the auxiliary lifting mechanism (5) are divided into multiple groups, and the number of auxiliary lifting mechanism units (51) in each group is the same as the number of racks (11) provided on the pile leg (1).

2. The gear and rack lifting hydraulic system based on an offshore platform according to claim 1, characterized in that: The main lifting mechanism unit (41) includes a fixed displacement motor (42), a first lifting solenoid valve (43), a second lifting solenoid valve (44), a first lifting relief valve (45), and a second lifting relief valve (46). The first lifting solenoid valve (43) and the second lifting solenoid valve (44) are both two-position normally closed solenoid valves. The oil inlet of the first lifting solenoid valve (43) is connected to the first oil outlet of the closed main pump (21), and the oil outlet of the first lifting solenoid valve (43) is connected to the A chamber of the fixed displacement motor (42). The oil inlet of the second lifting solenoid valve (44) is connected to the second oil outlet of the closed main pump (21). The oil ports are connected, the oil outlet of the second lifting solenoid valve (44) is connected to the B chamber of the metering motor (42), the oil discharge port of the metering motor (42) is connected to the oil tank, the oil inlet of the first lifting overflow valve (45) is connected to the oil outlet of the first lifting solenoid valve (43), the oil outlet of the first lifting overflow valve (45) is connected to the oil outlet of the second lifting solenoid valve (44), the oil inlet of the second lifting overflow valve (46) is connected to the oil outlet of the second lifting solenoid valve (44), and the oil outlet of the second lifting overflow valve (46) is connected to the oil outlet of the first lifting solenoid valve (43).

3. The gear and rack lifting hydraulic system based on an offshore platform according to claim 2, characterized in that: The auxiliary lifting mechanism unit (51) includes an auxiliary fixed displacement motor (52), a first auxiliary lifting solenoid valve (53), a second auxiliary lifting solenoid valve (54), a first auxiliary lifting overflow valve (55), and a second auxiliary lifting overflow valve (56). The first auxiliary lifting solenoid valve (53) and the second auxiliary lifting solenoid valve (54) are both two-position normally closed solenoid valves. The oil inlet of the first auxiliary lifting solenoid valve (53) is connected to the first oil outlet of the closed main pump (21), and the oil outlet of the first auxiliary lifting solenoid valve (53) is connected to the A chamber of the auxiliary fixed displacement motor (52). The oil inlet of the second auxiliary lifting solenoid valve (54) is connected to the second outlet of the closed main pump (21). The oil outlets are connected, the oil outlet of the second auxiliary lifting solenoid valve (54) is connected to the B chamber of the auxiliary quantitative motor (52), the oil discharge port of the auxiliary quantitative motor (52) is connected to the oil tank, the oil inlet of the first auxiliary lifting overflow valve (55) is connected to the oil outlet of the first auxiliary lifting solenoid valve (53), the oil outlet of the first auxiliary lifting overflow valve (55) is connected to the oil outlet of the second auxiliary lifting solenoid valve (54), the oil inlet of the second auxiliary lifting overflow valve (56) is connected to the oil outlet of the second auxiliary lifting solenoid valve (54), and the oil outlet of the second auxiliary lifting overflow valve (56) is connected to the oil outlet of the first auxiliary lifting solenoid valve (53).

4. A gear and rack lifting hydraulic system based on an offshore platform according to any one of claims 1 to 3, characterized in that: The isolation valve group (6) includes a first two-way cartridge valve (61), a second two-way cartridge valve (62), a first hydraulically controlled directional valve (63), a shuttle valve (64), a second hydraulically controlled directional valve (65), a third two-way cartridge valve (66), a first low-pressure shuttle valve (67), a first check valve (68), a second check valve (69), a second low-pressure shuttle valve (70), a back pressure check valve (71), a hydraulically controlled directional valve (72), and a throttle valve (73). The first two-way cartridge valve (61) and the second two-way cartridge valve (62) are normally open cartridge valves. The oil inlet of the first two-way cartridge valve (61) is connected to the A chamber of the fixed displacement motor (42) in the main lifting mechanism (4), and the oil outlet of the first two-way cartridge valve (61) is connected to the auxiliary... The auxiliary lifting mechanism (5) is connected to the A chamber of the fixed displacement motor (42), the oil inlet of the second two-way cartridge valve (62) is connected to the B chamber of the fixed displacement motor (42) in the main lifting mechanism (4), the oil outlet of the second two-way cartridge valve (62) is connected to the oil inlet of the B chamber of the fixed displacement motor (42) in the auxiliary lifting mechanism (5), the control ports of the first two-way cartridge valve (61) and the second two-way cartridge valve (62) are connected to the oil outlet of the first hydraulic directional valve (63), the control port of the first hydraulic directional valve (63) is connected to the oil outlet of the isolation valve group control valve (7), the unloading port of the first hydraulic directional valve (63) is connected to the oil tank, and the oil inlet of the first hydraulic directional valve (63) is connected to the oil outlet of the isolation valve group control valve (7). The outlet of the shuttle valve (64) is connected to the main lifting mechanism (4), the first inlet of the shuttle valve (64) is connected to the A chamber of the fixed displacement motor (42) in the main lifting mechanism (4), the second inlet of the shuttle valve (64) is connected to the B chamber of the fixed displacement motor (42) in the main lifting mechanism (4), the outlet of the shuttle valve (64) is connected to the inlet of the second hydraulic directional valve (65), the control port of the second hydraulic directional valve (65) is connected to the outlet of the isolation valve group control valve (7), the outlet of the second hydraulic directional valve (65) is connected to the control port of the third two-way cartridge valve (66), the unloading port of the second hydraulic directional valve (65) is connected to the oil tank, and the first outlet of the third two-way cartridge valve (66) is connected to the oil tank. The first oil inlet of the first low-pressure shuttle valve (67) is connected to the A chamber of the auxiliary lifting mechanism (5), the second oil outlet of the third two-way cartridge valve (66) is connected to the B chamber of the auxiliary lifting mechanism (5), the first oil inlet of the first low-pressure shuttle valve (67) is connected to the A chamber of the metering motor (42) in the main lifting mechanism (4), the second oil inlet of the first low-pressure shuttle valve (67) is connected to the B chamber of the metering motor (42) in the main lifting mechanism (4), the oil outlet of the first low-pressure shuttle valve (67) is connected to the oil inlet of the first one-way valve (68) and the second one-way valve (69), the oil outlet of the first one-way valve (68) is connected to the A chamber of the auxiliary lifting mechanism (5), and the second one-way valve (69) is connected to the B chamber of the auxiliary lifting mechanism (5).The first inlet of the second low-pressure shuttle valve (70) is connected to the outlet of the first two-way cartridge valve (61). The second inlet of the second low-pressure shuttle valve (70) is connected to the outlet of the second two-way cartridge valve (62). The outlet of the second low-pressure shuttle valve (70) is connected to the inlet of the throttle valve (73). The outlet of the throttle valve (73) is connected to the inlet of the hydraulic directional valve (72). The control port of the hydraulic directional valve (72) is connected to the outlet of the isolation valve group control valve (7). The outlet of the hydraulic directional valve (72) is connected to the inlet of the back pressure check valve (71). The outlet of the back pressure check valve (71) is connected to the oil tank.

5. A gear and rack lifting hydraulic system based on an offshore platform according to claim 4, characterized in that: The hydraulic oil pump (2) also includes a control pump (23). The main shaft of the control pump (23) is fixedly connected to the power output shaft of the motor (22). The oil inlet of the control pump (23) is connected to the oil tank. The oil outlet of the control pump (23) is connected to the oil inlet of the isolation valve group control valve (7). The oil outlet of the isolation valve group control valve (7) is connected to the oil tank.

6. A gear and rack lifting hydraulic system based on an offshore platform according to claim 4, characterized in that: The lifting hydraulic system also includes a brake control valve (8), which is a two-position three-position normally closed solenoid valve. The main lifting mechanism (4) also includes a main brake (47), and the auxiliary lifting mechanism (5) also includes an auxiliary brake (57). The oil inlet of the brake control valve (8) is connected to the oil outlet of the control pump (23). The working oil port of the brake control valve (8) is connected to the rodless chamber of each main brake (47) and each auxiliary brake (57). The oil outlet of the brake control valve (8) is connected to the oil tank.

7. The gear and rack lifting hydraulic system based on an offshore platform according to claim 1, characterized in that: The lifting device (3) includes a main lifting mechanism (4), multiple auxiliary lifting mechanisms (5), and multiple isolation valve groups (6). The number of auxiliary lifting mechanisms (5) is the same as the number of isolation valve groups (6). Each auxiliary lifting mechanism (5) is configured with an isolation valve group (6) to form an auxiliary lifting module. The auxiliary lifting modules formed by the auxiliary lifting mechanisms (5) and the isolation valve groups (6) are connected in series. The A chamber of each auxiliary lifting mechanism (5) is connected to the A2 port of its corresponding isolation valve group (6), and the B chamber of each auxiliary lifting mechanism (5) is connected to the B2 port of its corresponding isolation valve group (6). The A1 port of one isolation valve group (6) is connected to the A chamber of each main lifting mechanism unit (41), and the B1 port of one isolation valve group (6) is connected to the B chamber of each main lifting mechanism unit (41). The A1 ports of the remaining isolation valve groups (6) are sequentially connected to the A chamber of their corresponding auxiliary lifting mechanism units (51), and the B1 ports of the remaining isolation valve groups (6) are sequentially connected to the A chamber of their corresponding auxiliary lifting mechanism units (51). The lifting hydraulic system includes multiple isolation valve group control valves (7). The number of isolation valve group control valves (7) is the same as the number of isolation valve groups (6). Each isolation valve group control valve (7) is set to correspond to one isolation valve group (6). The on / off state between the A1 port and the A2 port of each isolation valve group (6) is controlled by its corresponding isolation valve group control valve (7).

8. A control method for a gear and rack lifting hydraulic system based on an offshore platform according to any one of claims 1 to 7, characterized in that: The control method includes the following steps: Step 1: Offshore platform erection. The operator drives the vessel to transport the offshore platform to the work area. After the offshore platform arrives at the work area, the operator turns on each motor (22) on the offshore platform and simultaneously controls the brake control valve (8), the first lifting solenoid valve (43), and the second lifting solenoid valve (44) to be energized. The motor (22) drives the corresponding closed main pump (21) to start working. At this time, the operator drives the control handle of the closed main pump (21) to open the first oil port of the closed main pump (21). The closed main pump (21) delivers hydraulic oil to the A chamber of each main lifting mechanism unit (41) and the rodless chamber of each main brake (47). At this time, the extension rod of the main brake (47) extends, which releases the lock of each main lifting mechanism unit (41). The gear (48) of each main lifting mechanism unit (41) rotates and drives the pile leg (1) to move downward. When the bottom of a certain pile leg (1) contacts the seabed and is limited by the seabed, the force between the pile leg (1) and the offshore platform causes the offshore platform to rise. At this time, the motor (22) corresponding to the pile leg (1) is turned off. When all motors (22) are turned off, the offshore platform pile-erecting step is completed. According to the offshore platform working conditions, the second step offshore platform rising step, the third step offshore platform descending step, or the fourth step offshore platform pile-lifting step are entered. Step 2: Elevation of the offshore platform. When the offshore platform needs to be elevated, the operator turns on each motor (22) and each built-in oil replenishment pump (24), and simultaneously controls the isolation valve group control valve (7), brake control valve (8), first lifting solenoid valve (43), second lifting solenoid valve (44), first auxiliary lifting solenoid valve (53), and second auxiliary lifting solenoid valve (54) to be energized. At this time, the A1 port and A2 port and the B1 port and B2 port of the isolation valve group (6) are connected. At this time, the operator drives the control handle of the closed main pump (21) to open the first oil port of the closed main pump (21), and the closed main pump (21) delivers hydraulic oil to each main lifting mechanism. In the A chamber of unit (41), the A chamber of each auxiliary lifting mechanism unit (51), the rodless chamber of each main brake (47) and each auxiliary brake (57), at this time the telescopic rods of the main brake (47) and the auxiliary brake (57) extend, causing the locking of each main lifting mechanism unit (41) and each auxiliary lifting mechanism unit (51) to be released, and the gears (48) in each main lifting mechanism unit (41) and each auxiliary lifting mechanism unit (51) rotate to drive the offshore platform to move upward. When the offshore platform reaches the designated height, the operator shuts off all motors (22) and the built-in oil pump (24), and at this time the offshore platform rising step is completed; Step 3: Lowering the offshore platform. When the offshore platform needs to be lowered, the operator turns on each motor (22) and each built-in oil replenishment pump (24), and simultaneously controls the isolation valve group control valve (7), brake control valve (8), first lifting solenoid valve (43), second lifting solenoid valve (44), first auxiliary lifting solenoid valve (53), and second auxiliary lifting solenoid valve (54) to be energized. At this time, the A1 port and A2 port and the B1 port and B2 port of the isolation valve group (6) are connected. At this time, the operator drives the control handle of the closed main pump (21) to open the second oil port of the closed main pump (21), and the closed main pump (21) delivers hydraulic oil to each main lifting mechanism. In the B chamber of unit (41), the B chamber of each auxiliary lifting mechanism unit (51), the rodless chamber of each main brake (47) and each auxiliary brake (57), at this time the telescopic rods of the main brake (47) and the auxiliary brake (57) extend, causing the locking of each main lifting mechanism unit (41) and each auxiliary lifting mechanism unit (51) to be released, and the gears (48) in each main lifting mechanism unit (41) and each auxiliary lifting mechanism unit (51) rotate to drive the offshore platform to move downward. When the offshore platform reaches the designated height, the operator shuts off all motors (22) and the built-in oil replenishment pump (24), at this time the offshore platform descent step is completed; Step 4: Piling the offshore platform. When the pile legs (1) need to be raised, the operator drives the vessel directly below the offshore platform and turns on each motor (22) and each built-in oil replenishment pump (24). At the same time, the isolation valve group control valve (7), brake control valve (8), first lifting solenoid valve (43), second lifting solenoid valve (44), first auxiliary lifting solenoid valve (53) and second auxiliary lifting solenoid valve (54) are energized. At this time, the A1 port and A2 port and the B1 port and B2 port of the isolation valve group (6) are connected. At the same time, the motor (22) drives the corresponding closed main pump (21) to start working. At this time, the operator drives the control handle of the closed main pump (21) to open the second oil port of the closed main pump (21). The closed main pump (21) delivers hydraulic oil to the B chamber of each main lifting mechanism unit (41), the B chamber of each auxiliary lifting mechanism unit (51), and each In the rodless chambers of the main brake (47) and each auxiliary brake (57), the telescopic rods of the main brake (47) and each auxiliary brake (57) extend, causing the locking of each main lifting mechanism unit (41) and each auxiliary lifting mechanism unit (51) to be released. The gears (48) in each main lifting mechanism unit (41) and each auxiliary lifting mechanism unit (51) rotate, driving the offshore platform to move downward. When the bottom of the offshore platform is at the limit with the top of the ship, the operator controls the disconnection between port A1 and port A2 and port B1 and port B2 of the isolation valve group (6) through the isolation valve group control valve (7). At this time, the gears (48) in each main lifting mechanism unit (41) rotate. At this time, the force between each pile leg (1) and the offshore platform causes all pile legs (1) to move upward. When all pile legs (1) have risen to the specified height, the offshore platform piling step is completed.

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