An LNG ship unloading arm

Abstract

The application discloses an LNG unloading arm for a ship, a pipeline system is connected with a main pipeline for conveying LNG on the ship through a rotary joint, is supported on an inner arm parallelogram support driving system and an outer arm parallelogram support driving system, an overall rotary driving device is connected with a mounting base and a main body of the LNG unloading arm for the ship through a rotary bearing, and the main body is driven to rotate through a hydraulic motor. The inner arm parallelogram support driving system and the outer arm parallelogram support driving system are driven to rotate through a splayed oil cylinder group, and drive the pipeline system to move synchronously; the LNG unloading arm for the ship is operated through a remote controller or an operation table, and is logically controlled through PLC. The application significantly reduces the installation column height of the LNG unloading arm for the ship, meets the unloading demand of a small ship at a low water level, reduces the overall structural size and weight of the LNG unloading arm, reduces the load on the ship body, and improves the running stability of the ship body.

Description

Technical Field

[0001] This invention belongs to the technical field of LNG transportation and transfer equipment, and in particular relates to an LNG unloading arm for use between ships at sea and between offshore platforms and ships. Background Technology

[0002] Currently, offshore liquefied natural gas (LNG) transportation units mainly come in two forms: LNG unloading arms and cryogenic hoses. LNG unloading arms offer advantages such as high throughput, long service life, and low flow resistance, making them widely used in high-volume offshore transportation. Most mainstream LNG unloading arms employ a rotary balance structure. To prevent interference during rotation, the LNG unloading arm's column is relatively tall. To meet the requirements of connecting to smaller vessels (with lower connection water levels), the overall structural dimensions of the LNG unloading arm need to be further increased, thus increasing the vessel's load and negatively impacting its stability. Summary of the Invention

[0003] The purpose of this invention is to solve the problems mentioned in the background art and provide an LNG ship unloading arm that significantly reduces the height of the installation column of the LNG ship unloading arm, meets the loading and unloading needs of small boats in low water levels, reduces the overall structural size and weight of the LNG unloading arm, reduces the load on the hull, and improves the stability of the hull operation.

[0004] To achieve the objective of this invention, an LNG ship unloading arm is disclosed, comprising a mounting base, an integral rotary drive device, and an LNG ship unloading arm body. The LNG ship unloading arm body is mounted above the mounting base via the integral rotary drive device. The LNG ship unloading arm body includes an inner arm parallelogram support drive system, an outer arm parallelogram support drive system, and a pipeline system. The inner arm parallelogram support drive system is driven to rotate by an inner arm figure-eight cylinder group, causing the pipeline supported on the inner arm to move synchronously. The outer arm parallelogram support drive system is driven to rotate by an outer arm figure-eight cylinder group, causing the pipeline supported on the outer arm to move synchronously. The LNG ship unloading arm can be remotely controlled via a remote control or operating console, causing the inner arm parallelogram support drive system and the outer arm parallelogram support drive system to move the pipeline system end docking device to the docking flange position of the LNG receiving vessel, establishing a delivery path.

[0005] Furthermore, the overall slewing drive device includes an external toothed slewing bearing and a hydraulic motor; the mounting base and the main body of the LNG ship unloading arm are connected by the external toothed slewing bearing, and the main body of the LNG ship unloading arm is driven to rotate by the hydraulic motor.

[0006] Furthermore, the inner arm parallelogram support drive system includes an inner arm main frame, an inner arm connecting rod, and an inner arm counterweight bracket. The inner arm main frame is hinged to the rotating mounting support on the overall rotary drive device. One end of the inner arm connecting rod is hinged to the support welded to the inner arm main frame, and the other end of the inner arm connecting rod is hinged to the support welded to the front end of the inner arm counterweight bracket. The middle part of the inner arm counterweight bracket is hinged to the upper support column hinged support on the overall rotary drive device through a rotary bearing. The above four hinge points form the four vertices of the parallelogram. The inner arm main frame and the inner arm counterweight bracket maintain the same rotation angle. The inner arm main frame is balanced in various movement positions by adjusting the weight of the inner arm counterweight bracket.

[0007] Furthermore, the inner arm figure-eight cylinder assembly is installed on the inner arm main frame. The inner arm figure-eight cylinder assembly consists of two cylinders, with steel wire ropes connected to the front ends of the cylinders. The steel wire ropes are connected to the inner arm drive pulley by buckles. The two cylinders of the inner arm figure-eight cylinder assembly maintain opposite directions of movement and have the same stroke. The inner arm main frame is driven to rotate by the extension and retraction of the two cylinders.

[0008] Furthermore, the outer arm parallelogram support drive system includes an outer arm main frame, an outer arm connecting rod, and an outer arm counterweight bracket. The middle part of the outer arm main frame is hinged to the inner arm main frame via a slewing bearing. One end of the outer arm connecting rod is hinged to a support welded to the outer arm main frame, and the other end of the outer arm connecting rod is hinged to a support welded to the front end of the outer arm counterweight bracket. The end of the outer arm counterweight bracket is hinged to the end of the inner arm main frame via a slewing bearing. The above four hinge points form the four vertices of a parallelogram. The outer arm main frame and the outer arm counterweight bracket maintain the same rotation angle. The counterweight balance of the outer arm main frame at various movement positions is achieved by adjusting the counterweight weight of the outer arm counterweight bracket.

[0009] Furthermore, the figure-eight hydraulic cylinder assembly of the outer boom is installed on the outer boom counterweight bracket. The figure-eight hydraulic cylinder assembly of the outer boom consists of two hydraulic cylinders. The front end of each hydraulic cylinder is connected to a steel wire rope, which is connected to the outer boom drive pulley by a buckle. The two hydraulic cylinders of the figure-eight hydraulic cylinder assembly maintain opposite directions of movement and have the same stroke. The outer boom counterweight bracket is driven to rotate by the extension and retraction of the two hydraulic cylinders, and the outer boom main frame is driven to rotate by the parallelogram mechanism.

[0010] Furthermore, the piping system includes an inner arm pipeline, an outer arm pipeline, and a rotary joint; the inner arm pipeline is supported on the inner arm main frame by a bracket, and the rotary joint on the inner arm pipeline and the slewing bearing for connecting the inner arm main frame and the rotating mounting support are coaxially installed; the rear end of the inner wall pipeline is connected to the liquid tank pipeline below the mounting base, and the liquid tank pipeline is connected to the liquid tank; the front end of the inner arm pipeline is hinged to the rear end of the outer arm pipeline by a rotary joint, and the rotary joint is located inside the slewing bearing for connecting the inner arm main frame and the outer arm main frame; the front end of the outer arm pipeline is connected to the outer arm main frame by a connecting bracket and the slewing bearing; the front end of the outer arm pipeline is equipped with three rotary joints with mutually perpendicular axes, realizing the rotation of the front end pipe body around the three axes; the front end of the outer arm pipeline is used to dock with the docking flange of the LNG receiving vessel; the front end of the outer arm pipeline is equipped with an emergency disconnection device and a quick connection device.

[0011] Furthermore, the LNG ship unloading arm is equipped with a hydraulic power unit and a PLC control unit. The hydraulic power unit is connected to the hydraulic actuator on the main body of the LNG ship unloading arm through hydraulic pipelines. The PLC control unit is installed in a remote control room. Control commands are sent to the PLC controller via a remote controller or operating console. The PLC controller controls the hydraulic power unit to provide hydraulic power to the hydraulic actuator on the main body of the LNG ship unloading arm, driving the movement of the LNG ship unloading arm.

[0012] Compared with the prior art, the significant advancement of the present invention is that it provides an LNG ship unloading arm with a double four-link drive, which significantly reduces the height of the LNG ship unloading arm installation column, meets the loading and unloading needs of small boats in low water levels, reduces the overall structural size and weight of the LNG unloading arm, reduces the load on the hull, and improves the stability of the hull operation.

[0013] To more clearly illustrate the functional characteristics and structural parameters of the present invention, further explanation is provided below in conjunction with the accompanying drawings and specific embodiments. Attached Figure Description

[0014] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings:

[0015] Figure 1 This is a front view of the LNG ship unloading arm assembly;

[0016] Figure 2 This is a rear view of the LNG ship's unloading arm assembly;

[0017] Figure 3 This is a schematic diagram of the inner arm parallelogram support drive system.

[0018] Figure 4This is a schematic diagram of the parallelogram support drive system for the outer arm;

[0019] Figure 5 This is a schematic diagram of the piping system.

[0020] Figure 6 This is a schematic diagram of the control system principle. Detailed Implementation

[0021] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] like Figure 1 , Figure 2 As shown, the LNG ship unloading arm consists of a mounting base 1, a rotating mounting support 4, an upper support column 5, an inner arm parallelogram support drive system 7, an outer arm parallelogram support drive system 9, and a piping system 8. The main body of the LNG ship unloading arm is connected to the mounting base 1 via a first slewing bearing 2. The first slewing bearing 2 is an external gear type, driven by a hydraulic motor 3 to rotate the entire arm. The two hinge points of the inner arm parallelogram support drive system 7 are connected to the rotating mounting support 4 and the upper support column hinge support 11 via a second slewing bearing 6 and a third slewing bearing 12, respectively. The two hinge points of the outer arm parallelogram support drive system 7 are connected to the front end and the end end of the inner arm main frame 7-1 via a fourth slewing bearing 10 and a fifth slewing bearing 13, respectively. The piping system 8 is supported on the inner arm parallelogram support drive system 7 and the outer arm parallelogram support drive system 9 via responsive brackets.

[0023] like Figure 3 As shown, the inner arm parallelogram support drive system consists of the inner arm main frame 7-1, the inner arm connecting rod 7-2, the inner arm counterweight bracket 7-3, and the inner arm figure-eight hydraulic cylinder group 7-7. One end of the inner arm connecting rod 7-2 is hinged to the first support 7-5 welded to the inner arm main frame 7-1, and the other end of the inner arm connecting rod 7-2 is hinged to the second support 7-5 welded to the front end of the inner arm counterweight bracket 7-3. The middle part of the inner arm counterweight bracket 7-3 is hinged to the upper support column hinge support 11 through the third slewing bearing 12. The inner arm main frame 7-1 is hinged to the rotating mounting support 4. The above four hinge points form the four vertices of a parallelogram (the parallelogram is shown by the thick black line 7-10 in the figure). According to the principle of parallelogram motion, the inner arm main frame 7-1 and the inner arm counterweight bracket 7-3 will maintain the same rotation angle. The inner arm main frame 7-1 is balanced in various movement positions by adjusting the weight of the counterweight 7-4.

[0024] like Figure 3 As shown, the inner arm figure-eight shaped hydraulic cylinder assembly 7-7 is installed on the inner arm main frame 7-1. It consists of two hydraulic cylinders, with a steel wire rope 7-8 connected to the front end of each cylinder. The steel wire rope 7-8 is connected to the inner arm drive rope pulley 4-1 via a buckle 7-9 (the inner arm drive rope pulley 4-1 is welded to the rotating mounting support 4). The inner arm figure-eight shaped hydraulic cylinder assembly 7-7 drives the inner arm main frame 7-1 to rotate around the axis of the inner arm drive rope pulley 4-1. The specific principle is as follows: when the left-hand (shown direction, the same below) hydraulic cylinder retracts, the left end of the steel wire rope 7-8 connected to it is tightened. Because the buckle 7-9 on the steel wire rope is fixedly connected to the inner arm drive rope pulley 4-1... On wheel 4-1 (the wire rope cannot slide on the wheel), under the tension on the left side of wire rope 7-8, the inner arm drives wheel 4-1 to rotate counterclockwise around its axis. At this time, the right side of wire rope 7-8 is simultaneously tightened, and the right cylinder extends outward simultaneously (the extension distance of the right cylinder is the same as the retraction distance of the left cylinder) to maintain the tension of the wire rope. Similarly, when the right cylinder retracts and the left cylinder extends, the inner arm drives wheel 4-1 to rotate clockwise around its axis. That is, through the opposite (one retracts, one extends) and identical stroke movements of the two cylinders in the inner arm figure-eight cylinder group 7-7, the rotation of the inner arm main frame 7-1 can be achieved.

[0025] like Figure 4 As shown, the outer boom parallelogram support drive system consists of the outer boom main frame 9-1, the outer boom counterweight bracket 9-2, the outer boom connecting rod 9-3, and the outer boom figure-eight hydraulic cylinder group 9-7. The outer arm main frame 9-1 is hinged to the inner arm main frame 7-1 at the middle via the fourth slewing bearing 10. One end of the outer arm connecting rod 9-3 is hinged to the third support 9-4 welded to the outer arm main frame 9-1, and the other end of the outer arm connecting rod 9-3 is hinged to the support welded to the front end of the outer arm counterweight bracket 9-2. The end of the outer arm counterweight bracket 9-2 is hinged to the end of the inner arm main frame 7-1 via the fifth slewing bearing 13. The above four hinge points form the four vertices of a parallelogram (the parallelogram is shown by the thick black line 9-10 in the figure). According to the principle of parallelogram motion, the outer arm main frame 9-1 and the outer arm counterweight bracket 9-2 will maintain the same rotation angle. The outer arm main frame 9-1 is balanced in various movement positions by adjusting the weight of the counterweight 9-6.

[0026] like Figure 4 As shown, the outer boom figure-eight cylinder assembly 9-7 is mounted on the outer boom counterweight bracket 9-2. It consists of two cylinders, with a steel wire rope 9-8 connected to the front end of each cylinder. The steel wire rope 9-8 is connected to the outer boom drive pulley 4-2 via a buckle 9-9 (the outer boom drive pulley 4-2 is welded to the rotating mounting bracket 4). The inner boom figure-eight cylinder assembly 9-7 drives the outer boom counterweight bracket 9-2 to rotate around the axis of the outer boom drive pulley 4-2. The specific principle is: when the left ( Figure 4(As shown in the direction, the same below) When the hydraulic cylinder retracts, the left end of the steel wire rope 9-8 connected to it is tightened. Because the buckle 9-9 on the steel wire rope is fixedly connected to the outer arm drive rope wheel 4-2 (the steel wire rope cannot slide on the rope wheel), under the action of the tension on the left side of the steel wire rope 9-8, the outer arm drive rope wheel 4-2 rotates counterclockwise around its axis. At this time, the right side of the steel wire rope 9-8 is simultaneously tightened, and the right hydraulic cylinder extends outward simultaneously (the extension distance of the right hydraulic cylinder is the same as the retraction distance of the left hydraulic cylinder) to maintain the tension of the steel wire rope. Similarly, when the right hydraulic cylinder retracts and the left hydraulic cylinder extends outward, the outer arm drive rope wheel 4-2 rotates clockwise around its axis. That is, through the opposite (one retracts, one extends) and same stroke movement of the two hydraulic cylinders of the outer arm figure-eight hydraulic cylinder group 9-7, the rotation of the outer arm counterweight support 9-2 can be realized.

[0027] like Figure 5 As shown, the piping system 8 consists of multiple pipeline sections and piping components such as rotary joints, emergency disconnection devices, and quick-connection devices. Specifically, the end of the inner arm pipeline 8-1 is supported on the inner arm main frame 7-1 by a bracket 8-4. The first rotary joint 8-3 on the inner arm pipeline 8-1 is coaxially mounted with the second slewing bearing 6 (used for connecting the inner arm main frame 7-1 and the rotating mounting support 4). The front end of the inner arm pipeline 8-1 is hinged to the rear end of the outer arm pipeline 8-2 by a second rotary joint 8-5, which is located inside the fourth slewing bearing 10 (used for connecting the inner arm main frame 7-1 and the outer arm main frame 9-1). The front end of the outer arm pipeline 8-2 is connected to the outer arm main frame 9-1 via a connecting bracket 8-7 and a slewing bearing 8-6. The piping system 8 achieves rotational support through two fulcrums, bracket 8-4 and connecting bracket 8-7, and can move synchronously with the inner arm main frame 7-1 and the outer arm main frame 9-1. The pipeline system 8 is equipped with a third rotary joint 8-8, a fourth rotary joint 8-9, and a fifth rotary joint 8-11 at its front end, which can enable the front-end pipeline to rotate around the x, y, and z axes. It is equipped with an emergency disconnect device 8-10 to allow for pipeline cut-off and separation in emergency situations, and a quick-connect device 8-12 to enable rapid connection with the docking flange.

[0028] Specifically, in this embodiment, one end of the third rotary joint 8-8 is connected to the front end of the outer arm pipeline 8-2 via a flange, and the other end of the third rotary joint 8-8 is connected to the upper end of the fourth rotary joint 8-9 via a bend in the pipe. The lower end of the fourth rotary joint 8-9 is connected to the emergency disconnect device 8-10 via a flange. One end of the fifth rotary joint 8-11 is connected to the lower part of the emergency disconnect device 8-10 via a bend in the pipe, and the other end is connected to the quick-connect device 8-12 via a flange.

[0029] like Figure 6As shown, the LNG ship unloading arm is equipped with a hydraulic power unit 01 and a PLC control unit 02. Control commands are sent to the PLC controller 04 via a remote control 03 or an operating console 04. The PLC controller 02 controls the hydraulic power unit 01 to provide hydraulic power to the hydraulic actuators on the LNG ship unloading arm, driving the arm's movement. The hydraulic power unit is located near the LNG ship unloading arm and is connected to the hydraulic actuators via hydraulic lines. The PLC control unit is installed in a remote control room. The hydraulic actuators consist of a hydraulic motor 3, an inner arm V-shaped cylinder group 7-7, and an outer arm V-shaped cylinder group 9-7.

[0030] The working process of the LNG ship unloading arm is as follows: after the LNG receiving vessel and the offshore LNG export terminal have completed the berthing operation, the LNG ship unloading arm is remotely extended to the docking flange position of the LNG receiving vessel via remote controller 03 or control panel 04, and the connection is completed through the front quick connection device 8-12 to establish the transportation channel. The motion principle of the LNG ship unloading arm is as follows: The main body of the LNG ship unloading arm is driven to rotate as a whole by a hydraulic motor 3; the inner arm's main frame 7-1 rotates around the inner arm drive pulley 4-1 via the inner arm's figure-eight cylinder group 7-7, and the inner arm's parallelogram support drive system maintains the counterweight balance during the rotation of the inner arm's main frame 7-1; the outer arm's main frame 9-1 rotates around the outer arm drive pulley 5-1 via the outer arm's figure-eight cylinder group 9-7, and the outer arm's parallelogram support drive system maintains the counterweight balance during the rotation of the outer arm's main frame 9-1; the pipeline system 8 has a third rotary joint 8-8, a fourth rotary joint 8-9, and a fifth rotary joint 8-11 at its front end, which can realize the rotation of the front-end pipeline around the x, y, and z axes. In summary, the quick-connect device 8-12 at the front end of the LNG ship unloading arm pipeline can achieve six degrees of freedom of movement in space, meeting the requirements for receiving the ship.

[0031] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0032] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A LNG ship unloading arm characterized by, The LNG unloading arm for ship comprises a mounting base, an integral rotary driving device and an LNG unloading arm body; the LNG unloading arm body is arranged above the mounting base through the integral rotary driving device; the LNG unloading arm body comprises an inner arm parallelogram support driving system, an outer arm parallelogram support driving system and a pipeline system; the inner arm parallelogram support driving system is driven to rotate through an inner arm eight-shaped oil cylinder group, and drives the pipeline supported on the inner arm to move synchronously; the outer arm parallelogram support driving system is driven to rotate through an outer arm eight-shaped oil cylinder group, and drives the pipeline supported on the outer arm to move synchronously; the LNG unloading arm for ship is remotely controlled through a remote controller or an operation table, so that the inner arm parallelogram support driving system and the outer arm parallelogram support driving system move, and drive the pipeline system end docking device to move to the docking flange position of the LNG receiving ship, and a conveying passage is established. The inner arm parallelogram support driving system comprises an inner arm main frame, an inner arm connecting rod and an inner arm counterweight support; the inner arm main frame is hinged to a rotary mounting support on the integral rotary driving device, one end of the inner arm connecting rod is hinged to a support welded on the inner arm main frame, the other end of the inner arm connecting rod is hinged to a support welded on the front end of the inner arm counterweight support, and the middle part of the inner arm counterweight support is hinged to a hinged support on the upper support column of the integral rotary driving device through a rotary support; the above four hinged points constitute four vertices of a parallelogram, the inner arm main frame and the inner arm counterweight support keep the same rotation angle, and the counterweight balance of the inner arm main frame at various movement positions is realized by adjusting the counterweight of the inner arm counterweight support. The outer arm parallelogram support driving system comprises an outer arm main frame, an outer arm connecting rod and an outer arm counterweight support; the middle part of the outer arm main frame is hinged to the inner arm main frame through a rotary support, one end of the outer arm connecting rod is hinged to a support welded on the outer arm main frame, the other end of the outer arm connecting rod is hinged to a support welded on the front end of the outer arm counterweight support, and the end of the outer arm counterweight support is hinged to the end of the inner arm main frame through a rotary support; the above four hinged points constitute four vertices of a parallelogram, the outer arm main frame and the outer arm counterweight support keep the same rotation angle, and the counterweight balance of the outer arm main frame at various movement positions is realized by adjusting the counterweight of the outer arm counterweight support.

2. A LNG ship offloading arm according to claim 1, characterized in that, The integral rotary driving device comprises an outer tooth-shaped rotary support and a hydraulic motor; the mounting base and the LNG unloading arm body are connected through the outer tooth-shaped rotary support, and the LNG unloading arm body is driven to rotate through the hydraulic motor.

3. A LNG ship offloading arm according to claim 1, characterized in that, The inner arm eight-shaped oil cylinder group is installed on the inner arm main frame and comprises two oil cylinders; a steel wire rope is connected to the front end of each oil cylinder and is connected to an inner arm driving rope wheel through a buckle; the two oil cylinders of the inner arm eight-shaped oil cylinder group keep opposite movement directions and have the same stroke, and the inner arm main frame is driven to rotate through the cooperation of the extension and contraction of the two oil cylinders.

4. A LNG ship offloading arm according to claim 3, characterized in that, The outer arm splayed oil cylinder group is installed on the outer arm counterweight support, the outer arm splayed oil cylinder group is composed of two oil cylinders, the front end of the oil cylinder is connected with a steel wire rope, the steel wire rope is connected on the outer arm driving rope wheel through a buckle, the two oil cylinders of the outer arm splayed oil cylinder group keep opposite movement directions and the same stroke, the outer arm counterweight support is driven to rotate through the extension and contraction cooperation movement of the two oil cylinders, and the outer arm main frame is driven to rotate through the parallelogram mechanism.

5. The LNG ship offloading arm of claim 1, wherein, The pipeline system comprises an inner arm pipeline, an outer arm pipeline and a rotary joint; the inner arm pipeline is supported on the inner arm main frame through a support, a rotary joint on the inner arm pipeline is coaxially installed with a slewing bearing for connecting the inner arm main frame with a rotary mounting support; a rear end of the inner wall pipeline is connected with a liquid tank pipeline below a mounting base, the liquid tank pipeline is connected with a liquid tank; a front end of the inner arm pipeline is hingedly connected with a rear end of the outer arm pipeline through the rotary joint, the rotary joint is located inside a slewing bearing for connecting the inner arm main frame with the outer arm main frame; a front end of the outer arm pipeline is connected on the outer arm main frame through a connecting support and the slewing bearing; the front end of the outer arm pipeline is provided with three rotary joints with three axes perpendicular to each other, rotation of the front end pipe body around the three axis directions is realized; the front end of the outer arm pipeline is provided with an emergency disengaging device and a quick connecting device.

6. A LNG ship offloading arm according to claim 1, characterized in that, The LNG ship unloading arm is provided with a hydraulic power unit and a PLC control unit, the hydraulic power unit is connected with hydraulic actuators on the LNG ship unloading arm body through hydraulic pipelines, and the PLC control unit is installed in a remote control room; control instructions are sent to the PLC controller through a remote controller or an operation table, the PLC controller controls the hydraulic power unit to provide hydraulic power for the hydraulic actuators on the LNG ship unloading arm body, and drives the LNG ship unloading arm to move.

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