Spraying method for ballast tank of LNG (Liquefied Natural Gas) ship

Abstract

The invention relates to an LNG ship ballast tank spraying method. The spraying method comprises the following steps that after the tank bottom, the groove-shaped tank wall, the first broadside and the second broadside of the ballast tank of the LNG ship are machined and formed correspondingly, assembling and spraying are carried out on the tank bottom, the groove-shaped tank wall, the first broadside and the second broadside; the supporting jig frame is adjusted according to the specification of the LNG ship ballast tank; the lower portion of the groove-shaped bulkhead and the cabin bottom are welded and assembled, and then the first broadside and the second broadside are welded and assembled with the cabin bottom and the groove-shaped bulkhead correspondingly; spraying is conducted through a spraying device; the spraying device comprises a supporting seat, a material conveying mechanism, a spraying mechanism, a horizontal swinging mechanism and an up-down swinging mechanism; a plurality of spray guns spray at the same time to improve the spraying efficiency; and after the groove-shaped bulkhead is sprayed, the broadside and the cabin bottom are sprayed. The method has the advantages that the ballast tank is sprayed after the groove-shaped tank wall, the broadside and the tank bottom are assembled and welded, so that damage to a coating of the ballast tank during groove-shaped processing of the groove-shaped tank wall and assembly and welding of all assemblies is reduced; the supporting jig frame can be suitable for assembling ballast tanks of different specifications; spraying is achieved through the spraying device, and the spraying efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of LNG ship ballast tank processing, and in particular to a LNG ship ballast tank spraying method. Background Art

[0002] Liquefied natural gas (LNG) carriers are vessels specifically designed to transport liquefied natural gas (LNG). They offer the advantages of large transport capacity and low cost, and are recognized worldwide for their high technology, high added value, and high reliability. Their service life extends over 40 years, during which they must maintain the ability to transport LNG at temperatures of -163°C. An LNG carrier's ballast tanks are compartments used to store ballast water to adjust the ship's navigational performance, including trim, list, draft, center of gravity, and stability. Common ballast tanks include forepeak, aftpeak, double bottom, gunwale, and deep tanks. Due to the frequent alternation of dry and wet conditions within ballast tanks, they are one of the most corrosive compartments on a ship. Therefore, coatings are required on the ballast tank plates to minimize corrosion.

[0003] In the prior art, when spraying ballast tanks, all the plates are usually sprayed first, and then operations such as transportation, welding, and in-tank trimming and grinding are carried out. These operations will inevitably damage the sprayed coating, and the coating damage is relatively serious. In addition, the ballast tank area has several trough-shaped transverse bulkheads. To ensure spraying efficiency, spraying is usually performed first and then troughing is performed, which will also damage the coating. If spraying is performed after the trough structure is formed, due to the special structure of the trough, the spraying operation is more troublesome and the spraying efficiency is low, requiring special spraying equipment. In addition, a corresponding support tire frame is also required for spraying. The existing support tire frame cannot be adjusted according to ballast tanks of different specifications, which is relatively inconvenient to use. Therefore, the present invention provides a LNG ship ballast tank spraying method to reduce coating damage and improve spraying efficiency. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method for spraying ballast tanks of LNG ships, which can solve the problems in the existing technology that the ballast tanks are first sprayed and then assembled, resulting in serious damage to the coating, the quality of the coating on the grooved transverse bulkheads in the ballast tank area cannot be guaranteed, the spraying efficiency is low, and the supporting frame used during spraying cannot be adjusted, resulting in inconvenience in use.

[0005] In order to solve the above technical problems, the technical solution of the present invention is as follows: S1. After the bottom, corrugated bulkhead, first side and second side of the LNG carrier's ballast tank are processed and formed, they are transported to the spray painting workshop for assembly and spray painting; S2. Assemble and weld by supporting the tire frame. Adjust the height and length of the support tire frame according to the specifications of the LNG ship ballast tank to adapt to the welding and spraying operation; S3. Support the bilge of the LNG carrier's ballast tank with a support frame, weld and assemble the lower portion of the corrugated bulkhead to the bilge of the ballast tank, and then weld and assemble the first side and the second side to the bilge and the corrugated bulkhead, respectively. S4. Spraying the corrugated bulkhead, the first side, and the second side respectively using a spraying device; The spraying device includes a support base, a feeding mechanism and a spraying mechanism; the feeding mechanism and the spraying mechanism are arranged on the support base, and the paint is fed to the spraying mechanism through the feeding mechanism; The spraying mechanism includes a column, a lifting frame, a translation plate and a spray gun, the column is fixed on the support seat, the lifting frame is a vertical frame structure, the lifting frame is driven by a hydraulic cylinder to move up and down along the longitudinal guide rail on the column, the spray gun is installed on the lifting frame through a translation plate, and the spray gun moves up and down with the lifting frame to change the spraying position, the translation plate is installed on the lifting frame, and the translation plate can be driven by a translation cylinder to translate along the transverse guide rail on the lifting frame, the translation cylinder is installed on the side of the lifting frame, and the movement of the translation plate drives the spray gun to translate to adjust the spraying position; The translation plate is provided with a plurality of spray guns, and the number of the spray guns is an odd number. The plurality of spray guns are respectively mounted on the translation plate through mounting plates. Adjacent mounting plates are connected by electric telescopic rods, and the mounting plate located in the middle position is fixed to the translation plate. The remaining mounting plates on both sides of the mounting plate in the middle position can be moved along the horizontal guide rail on the translation plate. The distance between the plurality of spray guns can be adjusted according to demand, and the plurality of spray guns spray at the same time to improve the spraying efficiency. The lifting frame is also provided with a horizontal swing mechanism for driving the spray gun to swing, so that the spray gun can swing horizontally for spraying, and the bottom of the support base is also provided with an up and down swing mechanism to adjust the tilt direction of the spray gun; During spraying, the length of the electric telescopic rod is first adjusted according to the specifications of the trough structure of the trough bulkhead to adjust the distance between the several spray guns. The translation cylinder then drives the translation plate to move to adjust the initial spraying position of the spray gun. The horizontal swing mechanism and hydraulic cylinder are then activated to drive the spray gun to swing horizontally and move up and down. The feeding mechanism delivers the paint to the spray gun, which then sprays the trough bulkhead. After the local spraying is completed, the mobile spraying device continues to spray the adjacent position, achieving spraying of the trough bulkhead from one side to the other. After the corrugated bulkhead is sprayed, the first and second side shells are sprayed; S5. Spray the bottom of the LNG ship's ballast tank. Before spraying, adjust the tilt direction of the spray gun through the up and down swing mechanism so that the spray direction of the spray gun is downward spraying. After the adjustment is completed, spray the bottom of the tank, and then assemble the remaining components of the LNG ship's ballast tank. Finally, spray the outside of the ballast tank to complete the spraying of the ballast tank.

[0006] Furthermore, in step S2, the support tire frame includes a track beam and a tire post that moves within the track beam, the track beam has a sunken track, the tire post moves laterally within the track, and a plurality of track beams are provided, and the plurality of track beams are arranged side by side; The track beam is provided with a plurality of tire columns, and the tire columns are a lifting structure. A connecting plate is fixed on the top of the tire column. The connecting plates on the tops of adjacent tire columns are connected by a splicing beam. The splicing beams have different specifications. The splicing beams of different specifications have different lengths and the same width. The top of the splicing beam is connected to a fixing groove, which is sunken inside the splicing beam. The top of the fixing groove is on the same horizontal line as the top of the splicing beam. A top column is connected to the fixing groove, and the multiple top columns have different heights. Among the plurality of tire posts, the tire posts on both sides are driven to move by the driving cylinder.

[0007] Furthermore, connecting slots are provided at both ends of the connecting plate, the splicing beams are passed through the connecting slots and fixed by locking bolts, and the tire column is driven to rise and fall by a spiral lifter; a distance measuring device is installed on the top side of the tire column.

[0008] Furthermore, in step S4, the feeding mechanism of the spraying device includes a material box, a feeding pump and a delivery pipe. The material box is installed on a support seat. The feeding pump delivers the paint in the material box to the spray gun through the delivery pipe. The delivery pipe is a hose. The discharge end of the delivery pipe is connected to several spray guns through several branch pipes. The branch pipes are also hoses. A stand is provided on the support seat, and one end of the delivery pipe close to the material box is fixed on the stand.

[0009] Furthermore, in step S4, the horizontal swing mechanism of the spraying device includes a rotating plate and a swing motor, the mounting plate of the spraying mechanism is an L-shaped mechanism, the bottom of the mounting plate is a horizontal base plate, the rotating plate is arranged above the base plate, an L-shaped fixing plate is fixed to the side of the spray gun, the spray gun is fixedly mounted on the rotating plate through the fixing plate, and the fixing plate and the rotating plate are fixed by bolts; The bottom of the rotating plate is connected to a rotating rod, which is arranged through the bottom plate of the mounting plate, and the rotating rod and the mounting plate are installed through a bearing. The rotating rod is arranged vertically, and the bottom of the rotating rod is connected to the output shaft of the swing motor through a coupling. The swing motor drives the rotating rod to rotate, which drives the rotating plate to rotate, thereby realizing the swing of the spray gun; The mounting plate is connected to a movable seat through a connecting frame. When the mounting plate moves horizontally, the movable seat is driven to move horizontally. The movable seat is arranged on the lower frame of the lifting frame, and the movable seat moves horizontally along the movable guide rail on the top of the lower frame of the lifting frame. The swing motor is installed on the top of the movable seat.

[0010] Furthermore, in step S4, the up and down swing mechanism of the spraying device includes a base, a connecting column and a hydraulic lifting column, the hydraulic lifting column and the connecting column are respectively arranged on the front and rear sides of the base, the support seat is arranged at the top of the connecting column and the hydraulic lifting column, and the bottom of the support seat is hinged to the top of the connecting column and the hydraulic lifting column respectively, the bottom of the base is provided with a moving wheel, and the inside of the base is provided with a motor assembly for driving the moving wheel to roll.

[0011] The advantages of the present invention are that the spray coating of the ballast tank is carried out after the assembly and welding of the corrugated bulkhead, the first side, the second side and the tank bottom are completed, thereby reducing the damage to the ballast tank coating during the groove processing of the corrugated bulkhead and the assembly and welding of various components; During assembly and welding, the support is provided by a support frame, which can be adjusted in length, height and width according to the actual specifications of the ballast tank. The height can be adjusted by raising and lowering the frame column, the length can be adjusted by splicing multiple splicing beams and connecting plates, and the width can be adjusted by using different numbers of track beams. It is suitable for the assembly of ballast tanks of different specifications, and the support frame can be reused multiple times, with flexible assembly and disassembly. Spraying is achieved through a spraying device. The spraying device is equipped with several spray guns. The distance between the several spray guns can be adjusted according to the groove structure of the grooved bulkhead. Several spray guns spray different groove structures at the same time to improve the spraying efficiency. The translation plate moves to adjust the initial position of the spray gun. The lifting frame can drive the spray gun to move up and down to change the spraying position. The horizontal swing mechanism can drive the spray gun to swing horizontally to achieve swing spraying of the spray gun. The up and down swing mechanism can adjust the inclination direction of the spray gun to facilitate the adjustment of the spray direction of the spray gun. The spray device can adjust the spray gun according to needs to adapt to the spraying operation. The spraying efficiency of the grooved bulkhead is improved, and the bottom, first side and second side can be sprayed efficiently, thereby improving the overall spraying efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a schematic diagram of the exploded structure of the LNG ship ballast tank of the present invention; Figure 2 It is a structural schematic diagram of the support tire frame of the present invention; Figure 3 This is a diagram showing the state of the support tire frame of the present invention supporting the ballast tank; Figure 4 It is a structural schematic diagram of the spraying device of the present invention; Figure 5 for Figure 4 A schematic diagram of the enlarged structure of region A; Figure 6 It is a schematic diagram of the installation structure of the spray gun of the spraying device of the present invention. DETAILED DESCRIPTION

[0013] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. The following examples can enable those skilled in the art to understand the present invention more comprehensively, but the present invention is not limited to the scope of the embodiments.

[0014] This specific implementation adopts the following technical solution: including the following steps: S1, after the bilge 10, the corrugated bulkhead 20, the first side 30 and the second side 40 of the LNG ship ballast tank are processed and formed respectively, they are transported to the spraying workshop for assembly and spraying. The structure of the LNG ship ballast tank is as follows Figure 1 shown.

[0015] S2. Assemble and weld by supporting the tire frame. Adjust the height and length of the support tire frame according to the specifications of the LNG ship ballast tank to adapt to the welding and spraying operation; like Figure 2 As shown, the supporting tire frame includes a track beam 11 and a tire column 13 that moves in the track beam 11. The track beam 11 has a sunken track 12. The tire column 13 moves laterally in the track 12. There are multiple track beams 11, and multiple track beams 11 are arranged side by side. The distance between the multiple track beams 11 can be adjusted, and the width of the tire frame can be changed. Multiple tire columns 13 are connected in the track beam 11. The tire columns 13 on both sides are driven to move by driving cylinders, and the driving cylinders can fix the positions of the tire columns 13 on both sides.

[0016] The tire column 13 is a lifting structure. The tire column 13 is driven by a spiral lifter to lift and adjust the height. A connecting plate 14 is fixed on the top of the tire column 13. The connecting plates 14 at the tops of adjacent tire columns 13 are connected by a splicing beam 15. The splicing beams 15 have different specifications. The splicing beams 15 of different specifications have different lengths and the same width. Connecting slots are provided at both ends of the connecting plate 14. The splicing beams 15 are passed through the connecting slots and fixed by locking bolts. The length can be adjusted by cooperating with the connecting plate 14 and the splicing beams 15. During actual assembly, shorter splicing beams 15 are set on the sides, and the splicing beams 15 set in the middle are slightly longer, which is more stable. The top of the splicing beam 15 It is connected with a fixing groove 16, which is sunken inside the splicing beam 15. The top of the fixing groove 16 is on the same horizontal line as the top of the splicing beam 15. A top column 17 is connected to the fixing groove 16. When the top column 17 is needed to increase the height, the top column 17 is interference fit in the fixing groove 16. If the increased part is not needed, it is directly supported on the top of the splicing beam 15 and the fixing groove 16. Multiple top columns 17 have different heights and are suitable for ballast tank bottoms of different heights. A distance measuring device is installed on the top side of the tire column 13. When the tire column 13 is raised or lowered, the distance measuring device can measure the height between the inner column and the outer column top of the tire column 13, and stop lifting when the requirement is met.

[0017] When assembling, it is supported by the support frame. According to the actual length of the ballast tank, the distance between the tire columns 13 on both sides is determined by the driving cylinder. The tire columns 13 can move in the track 12 of the track beam 11. The two driving cylinders are respectively connected to the tire columns 13 on both sides. The driving cylinder can control the tire columns 13 on both sides to fix their positions. Then the splicing beam 15 is clamped in the connecting groove at one end of the connecting plate 14 and fixed by the locking bolt. The other end of the splicing beam 15 is connected to the connecting plate 14 at the top of the adjacent tire column 13. The splicing beam 15 and the connecting plate 14 are fixed in sequence according to the required length to lengthen the total length. Since the positions of the tire columns 13 on both sides are fixed, the positions of the splicing beam 15 are fixed. After the remaining tire columns 13 in the middle move in the track 12, their positions are also fixed accordingly. Finally, according to requirements, the top column 17 is fixed with the fixing groove 16 by interference fit at the place where it needs to be raised. The top column 17 also has different heights, which can be selected according to needs. After use, each component can be removed in sequence for convenience of next use.

[0018] During assembly and welding, support is provided by a support frame, which can adjust the length, height and width according to the actual specifications of the ballast tank. The height can be adjusted by raising and lowering the tire column 3, the length can be adjusted by splicing multiple splicing beams 15 and connecting plates 14, and the width can be adjusted by different numbers of track beams 11. It is suitable for the assembly of ballast tanks of different specifications, and the support frame can be reused many times, and the combination installation and disassembly are flexible.

[0019] S3. Support the bilge 10 of the ballast tank of the LNG ship through a support frame, weld and assemble the lower part of the corrugated bulkhead 20 to the bilge 10 of the ballast tank, and then weld and assemble the first side 30 and the second side 40 to the bilge 10 and the corrugated bulkhead 20 respectively. The supporting state of the support frame during welding and assembly is as follows: Figure 3 As shown, the spraying of the ballast tank is carried out after the assembly and welding of the corrugated bulkhead 20, the first side 30, the second side 40 and the tank bottom 10 are completed, so as to reduce the damage to the ballast tank coating caused by the groove processing of the corrugated bulkhead 20 and the assembly and welding of each component.

[0020] S4. Spraying the corrugated bulkhead, the first side, and the second side respectively using a spraying device; like Figure 4 and Figure 5 As shown, the spraying device includes a support base 2, a feeding mechanism and a spraying mechanism; the feeding mechanism and the spraying mechanism are arranged on the support base 2, and the paint is fed to the spraying mechanism through the feeding mechanism.

[0021] The feeding mechanism of the spraying device includes a material box 31, a feeding pump and a delivery pipe 32. The material box 31 is installed on the support base 2. The feeding pump delivers the paint in the material box 31 to the spray gun 44 through the delivery pipe 32. The delivery pipe 32 is a hose. The discharge end of the delivery pipe 32 is connected to several spray guns 44 through several branch pipes 33. The branch pipes 33 are also hoses. A stand 34 is provided on the support base 2, and the end of the delivery pipe 32 close to the material box 31 is fixed on the stand 34.

[0022] The spraying mechanism includes a column 41, a lifting frame 42, a translation plate 43 and a spray gun 44. The column 41 is fixed on the support seat 2. The lifting frame 42 is a vertical frame structure. The lifting frame 42 is driven by a hydraulic cylinder to move up and down along the longitudinal guide rail on the column 41. The spray gun 44 is installed on the lifting frame 42 through the translation plate 43. The spray gun 44 moves up and down with the lifting frame 42 to change the spraying position. The translation plate 43 is installed on the lifting frame 42, and the translation plate 43 can be driven by a translation cylinder to translate along the transverse guide rail on the lifting frame 42. The translation cylinder is installed on the side of the lifting frame 42. There are two translation cylinders, which are respectively arranged on both sides of the translation plate 43. The movement of the translation plate 43 drives the spray gun 44 to translate to adjust the spraying position.

[0023] Several spray guns 44 are provided on the translation plate 43, and the number of the spray guns 44 is an odd number. The several spray guns 44 are respectively installed on the translation plate 43 through the mounting plates 45. In this embodiment, there are 3 spray guns 44. Adjacent mounting plates 45 are connected by electric telescopic rods 46, and the mounting plate 45 located in the middle position is fixed on the translation plate 43. The remaining mounting plates 45 on both sides of the mounting plate 45 in the middle position can be moved along the horizontal guide rail on the translation plate 43. The distance between the several spray guns 44 can be adjusted according to needs, and several spray guns 44 spray at the same time to improve the spraying efficiency.

[0024] The lifting frame 42 is also provided with a horizontal swing mechanism for driving the spray gun 44 to swing horizontally, so that the spray gun 44 can be sprayed horizontally; the horizontal swing mechanism includes a rotating plate 47 and a swing motor 48, such as Figure 6 As shown, the mounting plate 45 is an L-shaped structure, the bottom of the mounting plate 45 is a horizontal base plate, the rotating plate 47 is arranged above the base plate, and an L-shaped fixed plate 49 is fixed to the side of the spray gun 44. The spray gun 44 is fixedly mounted on the rotating plate 47 through the fixed plate 49. The fixed plate 49 and the rotating plate 47 are fixed by bolts. The rotation of the rotating plate 47 drives the spray gun 44 to swing accordingly.

[0025] A rotating rod 410 is connected to the bottom of the rotating plate 47. The rotating rod 410 is set through the bottom plate of the mounting plate 45, and the rotating rod 410 and the mounting plate 45 are installed through bearings. The rotating rod 410 is set vertically, and the bottom of the rotating rod 410 is connected to the output shaft of the swing motor 48 through a coupling. The rotating rod 410 is driven to rotate by the swing motor 48, which drives the rotating plate 47 to rotate, thereby realizing the swing of the spray gun 44.

[0026] The mounting plate 45 is connected to a movable seat 412 through a connecting frame 411. When the mounting plate 45 moves horizontally, the movable seat 412 is driven to move horizontally. The movable seat 412 is arranged on the lower frame of the lifting frame 42, and the movable seat 412 moves horizontally along the movable guide rail on the top of the lower frame of the lifting frame 42. The swing motor 48 is installed on the top of the movable seat 412.

[0027] The bottom of the support seat 2 is also provided with an up and down swinging mechanism to adjust the tilt direction of the spray gun 44. The up and down swinging mechanism includes a base 51, a connecting column and a hydraulic lifting column 52. The hydraulic lifting column 52 and the connecting column are respectively arranged on the front and rear sides of the base 51. The support seat 2 is arranged on the top of the connecting column and the hydraulic lifting column 52, and the bottom of the support seat 2 and the top of the connecting column and the hydraulic lifting column 52 are respectively hinged. A moving wheel is provided at the bottom of the base 51, and a motor assembly for driving the moving wheel to roll is provided inside the base 51. The base 51 is equivalent to a mobile cart and can realize overall movement.

[0028] The spraying device is provided with three spray guns 44. The distance between the three spray guns 44 can be adjusted according to the groove structure of the grooved bulkhead 20, and can be adjusted by the electric telescopic rod 46. The three spray guns 44 spray different groove structures at the same time. Since the position of the middle mounting plate 45 is fixed, the mounting positions of the three spray guns 44 on the translation plate 43 are limited. The three spray guns 44 spray at the same time to improve the spraying efficiency. The translation plate 43 moves to adjust the initial position of the spray gun 44. When there is a small deviation in the initial position, it can be adjusted by moving the translation plate 43. The lifting frame 42 moves up and down along the column 41, which can drive the spray gun 44 to move up and down, and the spraying position of the spray gun 44 can be changed. When the mounting plate 45 on which the spray gun 44 is mounted moves, the moving seat 4 is driven by the connecting frame 411. 12 moves synchronously to realize the synchronous translation of the swing motor 48. The swing motor 48 of the horizontal swing mechanism can drive the rotating plate 47 to rotate, drive the spray gun 44 to swing horizontally, and realize the swing spraying of the spray gun 44. The hydraulic lifting column 52 of the up and down swing mechanism can drive the support seat 2 to swing, so that the support seat 2 has a certain tilt direction, driving the spray gun 44 to have a certain tilt angle, and the spraying direction of the spray gun 44 can be adjusted to facilitate spraying in the top or bottom direction. The feed pump can transport the paint in the material box 31 to the spray gun 44 through the delivery pipe 32 to realize spraying. The spraying device can adjust the spray gun 44 as needed to adapt to the spraying operation. The trough bulkhead 20, the bottom of the cabin 10, the first side 30, and the second side 40 can all be sprayed efficiently, and the spraying efficiency is improved.

[0029] During spraying, the length of the electric telescopic rod 46 is first adjusted according to the specifications of the trough structure of the trough bulkhead 20 to adjust the distance between the multiple spray guns 44. The translation cylinder then drives the translation plate 43 to move to adjust the initial spraying position of the spray gun 44. The swing motor 48 of the horizontal swing mechanism is then activated to drive the spray gun 44 to swing horizontally. The hydraulic cylinder is then activated to drive the spray gun 44 to move up and down. The feeding mechanism delivers the paint to the spray gun 44 via a plastic pump. The spray gun 44 sprays the trough bulkhead. After the local spraying is completed, the mobile spraying device continues to spray adjacent positions, thereby spraying the trough bulkhead 20 from one side to the other. After the corrugated bulkhead 20 is sprayed, the first side 30 and the second side 40 are sprayed.

[0030] S5. Spray the bottom 10 of the ballast tank of the LNG ship. Before spraying, the tilt direction of the spray gun 44 is adjusted by the up and down swing mechanism so that the spray direction of the spray gun 44 is downward spraying. After the adjustment is completed, the spray gun 44 is driven to swing by the horizontal swing mechanism to perform swing spraying on the bottom 10. The spraying device moves as a whole to achieve full spraying of the bottom 10. Then, the remaining components of the ballast tank of the LNG ship are assembled. Finally, the outer side of the ballast tank is sprayed to complete the spraying of the ballast tank.

[0031] The above-mentioned drive cylinder, hydraulic cylinder, electric telescopic rod 46, translation cylinder, screw lifter, swing motor 48, feed pump, hydraulic lifting column 52, motor assembly and other components are all universal standard parts or components known to those skilled in the art. Their structures and principles can be known to those skilled in the art through technical manuals or through conventional experimental methods and will not be elaborated on.

[0032] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for spraying ballast tanks of LNG ships, characterized in that: The following steps are involved: S1. After the bilge, corrugated bulkhead, first side and second side of the LNG ship ballast tank are processed and formed respectively, they are transported to the spraying workshop for assembly and spraying; S2. Assemble and weld by supporting the tire frame, and adjust the height and length of the supporting tire frame according to the specifications of the LNG ship ballast tank to adapt to the welding spraying operation; S3. Support the bilge of the ballast tank of the LNG ship through a supporting frame, weld and assemble the lower part of the corrugated bulkhead to the bilge of the ballast tank, and then weld and assemble the first side and the second side to the bilge and the corrugated bulkhead respectively; S4. Spraying the grooved bulkhead, the first side, and the second side respectively by a spraying device; The spraying device comprises a support seat, a feeding mechanism and a spraying mechanism; the feeding mechanism and the spraying mechanism are arranged on the support seat, and the paint is transported to the spraying mechanism through the feeding mechanism; The spraying mechanism includes a column, a lifting frame, a translation plate and a spray gun, the column is fixed on the support seat, the lifting frame is a vertical frame structure, the lifting frame is driven by a hydraulic cylinder to move up and down along the longitudinal guide rail on the column, the spray gun is installed on the lifting frame through a translation plate, the spray gun moves up and down with the lifting frame to change the spraying position, the translation plate is installed on the lifting frame, and the translation plate can be driven by a translation cylinder to translate along the transverse guide rail on the lifting frame, the translation cylinder is installed on the side of the lifting frame, and the movement of the translation plate drives the spray gun to translate to adjust the spraying position; The translation plate is provided with a plurality of spray guns, and the number of the spray guns is an odd number, and the plurality of spray guns are respectively mounted on the translation plate through mounting plates, and adjacent mounting plates are connected by electric telescopic rods, and the mounting plate located in the middle is fixed on the translation plate, and the remaining mounting plates on both sides of the mounting plate in the middle can be moved along the horizontal guide rail on the translation plate, and the distance between the plurality of spray guns can be adjusted according to demand, and the plurality of spray guns spray at the same time to improve the spraying efficiency; The lifting frame is also provided with a horizontal swing mechanism for driving the spray gun to swing, so that the spray gun can swing horizontally for spraying, and the bottom of the support seat is also provided with an up and down swing mechanism, so as to adjust the tilt direction of the spray gun; During spraying, first adjust the length of the electric telescopic rod according to the specifications of the trough structure of the trough bulkhead to adjust the distance between several spray guns, then drive the translation plate to move through the translation cylinder to adjust the initial spraying position of the spray gun, then start the horizontal swing mechanism and hydraulic cylinder to drive the spray gun to swing horizontally and move up and down, the feeding mechanism conveys the paint to the spray gun, and the spray gun is sprayed on the trough bulkhead. After the local spraying is completed, the mobile spraying device continues to spray the adjacent position to realize the spraying of the trough bulkhead from one side to the other; After the grooved bulkhead is sprayed, the first side and the second side are sprayed; S5. Spray the bottom of the ballast tank of the LNG ship. Before spraying, adjust the tilt direction of the spray gun through the up and down swing mechanism so that the spray direction of the spray gun is downward spraying. After the adjustment is completed, spray the bottom of the tank, and then assemble the remaining parts of the ballast tank of the LNG ship. Finally, spray the outside of the ballast tank to complete the spraying of the ballast tank.

2. The method for spraying ballast tanks of an LNG ship according to claim 1, characterized in that: In step S2, the support tire frame includes a track beam and a tire column moving in the track beam, the track beam has a sunken track, the tire column moves laterally in the track, and a plurality of track beams are provided, and the plurality of track beams are arranged side by side; The track beam is provided with a plurality of posts, the posts are lifting structures, a connecting plate is fixedly provided on the top of the posts, the connecting plates on the tops of adjacent posts are connected by a splicing beam, the splicing beams have different specifications, the splicing beams of different specifications have different lengths and the same width, the top of the splicing beam is connected with a fixing groove, the fixing groove is sunken inside the splicing beam, the top of the fixing groove is on the same horizontal line as the top of the splicing beam, the fixing groove is connected with a top post, and the plurality of top posts have different heights; Among the plurality of tire pillars, the tire pillars on both sides are driven to move by the driving cylinder.

3. A method for spraying ballast tanks of LNG ships according to claim 2, characterized in that: Both ends of the connecting plate are provided with connecting slots, the splicing beams are passed through the connecting slots and fixed by locking bolts, and the tire column is driven to rise and fall by a spiral lifter; a distance measuring device is installed on the top side of the tire column.

4. The method for spraying ballast tanks of an LNG ship according to claim 1, characterized in that: In step S4, the feeding mechanism of the spraying device includes a material box, a feeding pump and a delivery pipe. The material box is installed on a support seat. The feeding pump delivers the paint in the material box to the spray gun through the delivery pipe. The delivery pipe is a hose. The discharge end of the delivery pipe is connected to several spray guns through several branch pipes, and the branch pipes are also hoses. A stand is provided on the support seat, and one end of the delivery pipe close to the material box is fixed on the stand.

5. The method for spraying ballast tanks of an LNG ship according to claim 1, characterized in that: In the step S4, the horizontal swing mechanism of the spraying device includes a rotating plate and a swing motor, the mounting plate of the spraying mechanism is an L-shaped mechanism, the bottom of the mounting plate is a bottom plate in the horizontal direction, the rotating plate is arranged above the bottom plate, an L-shaped fixing plate is fixed on the side of the spray gun, the spray gun is fixedly mounted on the rotating plate through the fixing plate, and the fixing plate and the rotating plate are fixed by bolts; The bottom of the rotating plate is connected with a rotating rod, the rotating rod is arranged through the bottom plate of the mounting plate, and the rotating rod and the mounting plate are installed through a bearing, the rotating rod is arranged vertically, the bottom of the rotating rod is connected to the output shaft of the swing motor through a coupling, the swing motor drives the rotating rod to rotate, drives the rotating plate to rotate, and realizes the swing of the spray gun; The mounting plate is connected to a moving seat via a connecting frame. When the mounting plate moves horizontally, the moving seat is driven to move horizontally. The moving seat is arranged on a frame below the lifting frame, and the moving seat moves horizontally along a moving guide rail on the top of the frame below the lifting frame. The swing motor is installed on the top of the moving seat.

6. The method for spraying ballast tanks of an LNG ship according to claim 1, characterized in that: In step S4, the up and down swing mechanism of the spraying device includes a base, a connecting column and a hydraulic lifting column, the hydraulic lifting column and the connecting column are respectively arranged on the front and rear sides of the base, the support seat is arranged on the top of the connecting column and the hydraulic lifting column, and the bottom of the support seat is hinged to the top of the connecting column and the hydraulic lifting column respectively, the bottom of the base is provided with a moving wheel, and the inside of the base is provided with a motor assembly for driving the moving wheel to roll.

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