A method for mounting a total assembly of a bottom section of an LNG ship engine room and a bottom section of an LNG ship engine room

Abstract

The present invention discloses a method for mounting a total assembly of the bottom section of the engine room of an LNG ship. The design method comprises the following steps: S1, setting a total assembly cradle of the bottom section of the engine room, S2, first segment positioning, S3, second segment assembly, S4, third segment assembly, S5, fourth segment assembly, S6, fifth segment assembly, S7, setting a cradle for mounting the bottom section of the engine room, S8, dock mounting the bottom section of the engine room. The present invention adopts an efficient cradle design method, which is in line with the characteristics of the double-shaft engine room section of the LNG ship, can improve the mounting accuracy and efficiency of the bottom section of the engine room of the LNG ship, and improves the level of safe construction, can improve the installation accuracy of the main engine of the LNG ship, and ensure the propulsion efficiency of the LNG ship during operation.

Description

Technical Field

[0001] The present invention belongs to the technical field of shipbuilding, and in particular relates to a method for assembling a bottom layer block of an LNG ship engine room and a bottom layer block of an LNG ship engine room obtained according to the method. Background Art

[0002] During the assembly and loading process of the bottom section of the engine room of the LNG ship, the quality of its assembly and loading directly determines the installation accuracy of the subsequent double-shaft main engine, affecting the construction efficiency of the LNG ship and the propulsion efficiency during operation.

[0003] In the prior art, Chinese patent application document 201110076622.9 discloses a method for assembling a cabin section and hoisting the cabin section. The invention combines 13 sections into one section. Although the integrity of the installation of the section structure can be ensured, there is no requirement for precision control.

[0004] At present, the conventional LNG ship engine room bottom section assembly and loading process cannot well control the accuracy of the engine room bottom section assembly and loading, and there are a lot of safety hazards, which greatly prolongs the construction period. The conventional construction method has the following shortcomings:

[0005] First, there is a lack of effective means for setting the tire position during the assembly and loading of the bottom section of the LNG ship engine room. The existing design of the assembly and loading tire frame of the bottom section of the LNG ship engine room does not take into account the characteristics of the double-shaft engine room section, resulting in low accuracy in the assembly and loading of the bottom section of the LNG ship engine room, a particularly long assembly and loading cycle, and many safety hazards during the assembly and loading process.

[0006] Second, there is a lack of effective precision control means for the assembly of the bottom section of the LNG ship engine room and the assembly of each section during the loading process. The existing LNG ship engine room bottom section assembly and the loading process do not have a suitable matching line setting, and the precision control means are scarce, making it difficult to achieve rapid uncoupling during the assembly of the section and the loading process.

[0007] Third, there is a lack of effective welding methods for the assembly of the subsections in the process of LNG ship engine room bottom section assembly. The existing LNG ship engine room bottom section assembly has an unreasonable assembly and welding sequence of the subsections, resulting in large deformation of the double bottom section of the engine room. The half-width, length and height dimensions cannot be effectively controlled, and the accuracy of the engine room bottom section is extremely easy to exceed the tolerance.

[0008] Fourth, there is no good means to control the horizontality of the main engine base panel during the assembly of the bottom section of the engine room of the LNG ship and the loading process. The main engine base panel is not well controlled during the assembly of the bottom section of the engine room of the existing LNG ship and the loading process. In particular, the relative position relationship between the main engine base panel, the center line of the shaft system, and the hull baseline is difficult to control, which will cause the center line of the shaft system to be out of tolerance, and the thickness of the epoxy cannot be accurately controlled. In severe cases, it may also cause heating of the shaft system, which will ultimately affect the propulsion efficiency during the subsequent operation of the LNG ship. Summary of the invention

[0009] In view of the problems existing in the prior art, the present invention provides a method for assembling and mounting the bottom layer of the engine room of an LNG ship, which overcomes the problems that in the conventional assembly and mounting process of the bottom layer of the engine room of an LNG ship, the accuracy of the assembly and mounting of the bottom layer of the engine room cannot be well controlled, and there are a large number of safety hazards, as well as a long construction period and low construction accuracy.

[0010] The present invention solves the above technical problems through the following technical solutions:

[0011] A method for assembling and mounting a bottom layer section of an engine room of an LNG ship, wherein the bottom layer section of the engine room of the LNG ship structurally comprises a first section, a second section, a third section, a fourth section and a fifth section, wherein the first section and the third section are symmetrically distributed on both sides of the second section, the middle portion of the rear side of the second section is spliced ​​with the fourth section and the fifth section, and the fourth section and the fifth section are arranged in a left-right relationship. The method is characterized in that the first section, the second section, the third section, the fourth section and the fifth section are respectively manufactured by marking and positioning and arranging a tire frame, and then they are hoisted, welded and assembled one by one, and the five sections are assembled to form a bottom layer section of the engine room, and then the assembled bottom layer section of the engine room is mounted on a dock.

[0012] The method for mounting the overall assembly of the bottom section of the engine room of an LNG ship specifically comprises the following steps:

[0013] S1, set up the general assembly cradle of the engine room bottom section, first mark the line on the general assembly platform, mark the center ground line of the hull, the FR38 rib ground line is based on the hull center ground line to make the cradle longitudinal section ground line group, and then make the rib position ground line group according to the FR38 rib ground line. The intersection of the cradle longitudinal section ground line group and the rib position ground line group is the cradle process part position point. After the ground line survey is completed, the general assembly cradle ground line of the LNG ship engine room bottom section is formed; the cement dock pier group and the support group are arranged according to the cradle process part position point; according to the hull center ground line, mark the center ground line of the port main engine base and the center ground line of the starboard main engine base, and according to the FR38 rib ground line, mark another FR60 rib ground line;

[0014] S2, positioning the first segment. After the first segment is hoisted into place, tighten the spiral support head on the support group, knock the slats on the cement dock pier group, and use the segmented channel steel tie rods to connect with the pre-buried iron of the main group floor;

[0015] S3, second segment assembly, according to the height position of the second segment, hoist the second segment into place, after positioning, weld the second segment and the first segment at the bow and stern ends of the second segment, the welding order is from the middle to the bow and stern direction;

[0016] S4, the third section assembly, after the third section is hoisted into place, tighten the spiral support head on the support group, knock the slats of the cement dock pier group, and weld the positioning restraint weld between the third section and the second section at the bow and stern ends of the third section. The welding order is from the middle to the bow and stern direction;

[0017] S5, the fourth section assembly, after the fourth section is hoisted into place, tighten the spiral support head on the support group, knock the slats on the cement dock pier group, and weld the positioning constraint weld between the fourth section and the first section at the left and right ends of the fourth section. The welding order is from the middle to the left and right directions;

[0018] S6, the fifth section assembly, after the fifth section is hoisted into place, tighten the spiral support head on the support group, knock the slats on the cement dock pier group, weld the positioning constraint weld between the fifth section and the third section at the left and right ends of the fifth section, weld the constraint plate between the fifth section and the fourth section at the bow and stern ends of the fifth section, all welding adopts double-sided continuous welding, the ends should be angled, the height of the weld leg is 0.7 times the plate thickness, the height of the weld leg at the angle is 0.8 times the plate thickness, and the order of welding is from the middle to the left and right directions;

[0019] S7, set up a cradle for the engine room bottom section, open a hull center ground line of the dock area on the dock floor, open a FR40 rib ground line out of the dock area according to the hull center ground line, open a group of longitudinal sections out of the dock area according to the hull center ground line, open a group of rib ground lines out of the dock area according to the FR40 rib ground line of the dock area, open a group of dock pier position marks according to a group of longitudinal sections in the dock area and the FR40 rib ground line of the dock area, form a dock ground line for the bottom section of the LNG ship engine room, set up a group of dock supports according to the intersection of a group of rib ground lines in the dock area and a group of longitudinal sections in the dock area, and arrange a group of dock piers according to the position marks of a group of dock piers;

[0020] S8, the engine room bottom section is docked. Four shaft system benchmarks are set up on the engine room bottom section. The shaft system centerline is made at a distance of L0 from the inner bottom plate. The hull baseline is made on a set of dock piers. The engine room bottom section is hoisted into place so that the distance between the shaft system centerline and the hull baseline is L1. The hull centerline of the section is aligned with the hull centerline of the dock bottom. The FR40 rib position line of the engine room bottom section is aligned with the FR40 rib position ground line of the dock bottom. The section channel steel tie rod is used to connect with the embedded iron of the dock floor to complete the loading of the engine room bottom section.

[0021] As a preferred technical solution, in step S1, the straightness deviation of the hull center ground line and the FR38 rib ground line is 1mm, and the verticality deviation is 1mm; the straightness deviation of the tire frame longitudinal section ground line group and the rib ground line group is 2mm, and the verticality deviation is 2mm; the parallelism error of the hull center ground line and the center ground line of the port main engine base and the center ground line of the starboard main engine base is 1mm, the parallelism error of the FR38 rib ground line and the FR60 rib ground line is 1mm, and the verticality error between the FR38 rib ground line, the FR60 rib ground line, the hull center ground line, the port main engine base center ground line, and the starboard main engine base center ground line is 2mm.

[0022] As a preferred technical solution, in the steps S2-S6, the cement dock group and the support group are arranged according to the position points of the tire frame process parts. The front, rear, left and right deviations of the center positions of the cement dock group and the support group and the position points of the tire frame process parts should be less than 20 mm. In the steps S1-S6, before hoisting each segment, the segment FR38 rib position line, each segment center line, and the horizontal monitoring points of the segment host base panel are made on each segment. After the segment is hoisted, the horizontality of the horizontal monitoring points of the segment host base panel is monitored, and the base panel of the host on the segment is adjusted to be horizontal. The allowable deviation of the horizontal monitoring points of the segment host base panel is 3 mm.

[0023] As a preferred technical solution, in steps S2-S6, the position of each segment is adjusted so that the segment FR38 rib position line is aligned with the FR38 rib ground line on the ground, with an allowable accuracy deviation of 2 mm, and the center line of each segment main engine base is aligned with the center ground line of the port side main engine base on the ground, with an allowable deviation of 2 mm.

[0024] As a preferred technical solution, after the segment positioning is completed in step S3, a positioning constraint weld is welded between the second segment and the first segment at a distance of 300 mm from the bow and stern ends of the second segment. The weld length of the positioning constraint weld is 490 to 510 mm. A groove is opened between the second segment and the first segment, and the groove gap is 5 to 8 mm.

[0025] As a preferred technical solution, in step S4, a positioning restraint weld is welded between the third segment and the second segment at a distance of 300 mm from the bow and stern ends of the third segment, the weld length of the positioning restraint weld is 490 to 510 mm, and a groove is opened between the third segment and the second segment, and the groove gap is 5 to 8 mm.

[0026] As a preferred technical solution, in step S5, a positioning constraint weld is welded between the fourth segment and the first segment at a distance of 300 mm from the left and right ends of the fourth segment, the weld length of the positioning constraint weld is 490 to 510 mm, and a groove is opened between the fourth segment and the first segment, and the groove gap is 5 to 8 mm.

[0027] As a preferred technical solution, in step S6, a positioning constraint weld is welded between the fifth segment and the third segment at a distance of 300 mm from the left and right ends of the fifth segment, and the weld length of the positioning constraint weld is 490 to 510 mm. A constraint horse plate is welded between the fifth segment and the fourth segment at a distance of 300 mm from the bow and stern ends of the fifth segment, and a groove is formed on the constraint horse plate between the fifth segment and the third segment, and a groove gap is 5 to 8 mm.

[0028] As a preferred technical solution, in step S7, the verticality between the center ground line of the dock hull and the FR40 rib ground line of the dock area is controlled at 2 mm, a group of dock supports are set according to the intersection of a group of rib ground lines in the dock area and a group of longitudinal sections in the dock area, and the front, rear, left, and right deviations of a group of dock supports are required to be less than 20 mm, and a group of dock piers are arranged according to the position marks of a group of dock piers, and the front, rear, left, and right deviations of a group of dock piers are less than 20 mm.

[0029] As a preferred technical solution, in step S8, the positions of a group of dock supports and a group of dock piers have a front, rear, left and right deviation of less than 30 mm, the bottom section of the engine room is hoisted into place, so that the distance between the center line of the shaft system and the baseline of the hull is L1, the allowable deviation range is 0 to 2 mm, the center line of the hull of the section is aligned with the center line of the hull of the dock bottom, the FR40 rib position line of the bottom section of the engine room is aligned with the FR40 rib position ground line of the dock bottom, the deviation is less than 2 mm, the horizontality of the horizontal monitoring points on the bottom plate of the bottom section of the engine room is monitored, and the allowable deviation of the horizontal monitoring points on the bottom plate of the bottom section of the engine room is less than 4 mm.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] 1. The present invention adopts an efficient tire frame design method, which is in line with the characteristics of the double-shaft engine room section of the LNG ship, can improve the loading accuracy and loading efficiency of the bottom section of the engine room of the LNG ship, and improve the level of safe construction.

[0032] 2. The present invention provides a scientific method for setting the joint line of the bottom section of the engine room of an LNG ship, which can conveniently and quickly realize the rapid uncoupling of the bottom section of the engine room of an LNG ship during the assembly and loading process.

[0033] 3. The scientific and reasonable welding method provided by the present invention can achieve precision control of the half-width, length and height directions of the overall section of the bottom layer of the engine room of the LNG ship.

[0034] 4. This invention provides a good control solution for the horizontality of the main engine base panel of the bottom section of the engine room of the LNG ship, which can improve the installation accuracy of the main engine of the LNG ship and ensure the propulsion efficiency of the LNG ship during operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0036] Figure 1 It is a schematic diagram of the ground line marking of the overall section and overall assembly frame of the cabin bottom layer of the present invention.

[0037] Figure 2 It is a schematic diagram of the overall assembly dock pier and overall assembly support of the bottom layer of the cabin of the present invention.

[0038] Figure 3 It is a schematic diagram of the first subsection positioning of the bottom floor of the cabin of the present invention.

[0039] Figure 4 It is a schematic diagram of the second subsection assembly of the bottom layer of the cabin of the present invention.

[0040] Figure 5 It is a schematic diagram of the third subsection of the bottom layer of the cabin of the present invention.

[0041] Figure 6 It is a schematic diagram of the fourth subsection of the cabin bottom layer of the present invention.

[0042] Figure 7 It is a schematic diagram of the fifth subsection of the bottom layer of the cabin of the present invention.

[0043] Figure 8 It is a schematic diagram of the line drawing of the tire frame of the bottom section of the cabin of the present invention.

[0044] Fig. 9 It is a schematic diagram of the mounting dock and mounting support of the bottom section of the cabin of the present invention.

[0045] Fig.10It is a schematic diagram of the installation of the bottom layer of the cabin of the present invention.

[0046] Wherein, the accompanying drawings are marked as follows:

[0047] 1—cradle ground line of the bottom section of the engine room of the LNG ship; 1-1—hull center ground line; 1-2—FR38 rib inspection ground line; 1-3—cradle longitudinal section ground line group; 1-4—rib position ground line group; 1-3-4—cradle process parts position point; 1-5—port main engine base center ground line; 1-6—starboard main engine base center ground line; 1-7—FR60 rib inspection ground line; 2—cement dock group; 2-1—a group of ribs on the cement dock; 3—support group; 3-1—screw support head on the support group; 4—first section; 4-1—FR38 rib position line of the first section; 4-2—first section main engine base center line; 4-3—first section main engine base panel horizontal monitoring point; 4-4—channel steel tie rod; 4-4—channel steel tie rod; 4 -5—pre-buried iron of the general assembly floor; 5—second section; 5-1—FR38 rib position line of the second section; 5-2—center line of the second section; 5-4-1—positioning constraint weld between the second section and the first section; 5-4-2—weld between the second section and the first section; 5-4-3—sequence of welding between the second section and the first section; 6—third section; 6-1—FR38 rib position line of the third section; 6-2—center line of the host base of the third section; 6-3—horizontal monitoring point of the host base panel of the third section; 6-5-1—positioning constraint weld between the third section and the second section; 6-5-2—weld between the third section and the second section; 6-5-3—sequence of welding between the third section and the second section; 7—fourth section ;7-1—FR60 rib position line of the fourth section;7-2—center line of the main engine base of the fourth section;7-3—horizontal monitoring point on the bottom plate of the fourth section;7-4-1—positioning constraint weld between the fourth section and the first section;7-4-2—weld between the third section and the second section;7-4-3—sequence of welding between the fourth section and the first section;8—fifth section;8-1—FR60 rib position line of the fifth section;8-2—center line of the fifth section;8-3—horizontal monitoring point on the bottom plate of the fifth section;8-6-1—positioning constraint weld between the fifth section and the third section;8-7-1—constraint plate between the fifth section and the fourth section;8-6-2—weld between the fifth section and the third section;8-6-3—fifth section The welding sequence between the block and the third block; 9—LNG ship engine room bottom section dock ground line; 9-1 dock area hull center ground line; 9-2—FR40 rib position ground line in the dock area; 9-3—a group of longitudinal sections in the dock area; 9-4—a group of rib position ground lines in the dock area; 9-4—a group of rib position ground lines in the dock area; 9-6-1—a group of dock pier position marks; 9-6—a group of dock piers; 10—engine room bottom section; 10-1—engine room bottom section center line; 10-2—engine room bottom section FR40 rib position line; 10-3—horizontal monitoring point on the bottom plate of the engine room bottom section; 10-4—shaft system benchmark; 10-4-1—shaft system center line; 10-4-2—hull baseline; 10-4—section channel steel tie rod;10-5—Pre-buried iron in the dock floor. ; DETAILED DESCRIPTION

[0048] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0049] like Figures 1 to 10 As shown, in this embodiment, x is in the reverse direction of the bow and stern of the ship length, y is in the left and right direction of the ship width, and z is in the up and down direction of the ship height. This embodiment provides a method for mounting a total assembly of the bottom section of the engine room of an LNG ship, and the total assembly and mounting method include the following steps:

[0050] S1, set up the assembly frame of the bottom section of the engine room. Figure 1 As shown, firstly, marking is performed on the general assembly platform to mark out the hull center ground line 1-1 and the FR38 rib inspection ground line 1-2. The straightness deviation of the hull center ground line 1-1 and the FR38 rib inspection ground line 1-2 is 1mm, and the verticality deviation of the hull center ground line 1-1 and the FR38 rib inspection ground line 1-2 is 1mm; the tire frame longitudinal section ground line group 1-3 is made according to the hull center ground line 1-1, and the rib position ground line group 1-4 is made according to the FR38 rib inspection ground line 1-2. The straightness deviation of the tire frame longitudinal section ground line group 1-3 and the rib position ground line group 1-4 is 2mm, and the verticality deviation of the tire frame longitudinal section ground line group 1-3 and the rib position ground line group 1-4 is 2mm. The intersection of the tire frame longitudinal section ground line group 1-3 and the rib position ground line group 1-4 is the tire frame process part position point 1-3-4. After the above ground line survey is completed, the LNG ship engine room bottom section general assembly tire frame ground line 1 is formed; as shown Figure 2 As shown, the cement dock group 2 and support group 3 are arranged according to the tire frame process part position point 1-3-4. The center position of the cement dock group 2 and support group 3 should have a front-to-back and left-to-right deviation from the tire frame process part position point 1-3-4 of less than 20mm. Figure 3 As shown, according to the hull center ground line 1-1, the center ground line 1-5 of the port main engine base and the center ground line 1-6 of the starboard main engine base are drawn, and according to the FR38 rib ground line 1-2, another FR60 rib ground line 1-7 is drawn, the parallelism error between the hull center ground line 1-1 and the center ground line 1-5 of the port main engine base and the center ground line 1-6 of the starboard main engine base is 1mm, the parallelism error between the FR38 rib ground line 1-2 and the FR60 rib ground line 1-7 is 1mm, and the verticality error between the FR38 rib ground line 1-2, the FR60 rib ground line 1-7, the hull center ground line 1-1, the port main engine base center ground line 1-5 and the starboard main engine base center ground line 1-6 is 2mm.

[0051] S2, segment 1, segment 4 positioning, e.g. Figure 3 As shown, check the position of cement dock group 2 and support group 3 again. If the position of cement dock group 2 and support group 3 is changed by the impact of construction equipment, it is necessary to re-place cement dock group 2 and support group 3 to the correct position to ensure that the center position of cement dock group 2 and support group 3 and the front, back, left and right deviations of the tire frame process part position point 1-3-4 should be less than 20mm. Before the first section 4 is hoisted, the first section FR38 rib position line 4-1, the first section 4 main engine base center line 4-2, and the first section 4 main engine base panel horizontal monitoring point 4-3 are made on the section 4. The first section 4 is hoisted in place and placed on the cement dock group 2 and support group 3. The position of the first section 4 is adjusted so that the FR38 rib position line 4-1 of the first section 4 is aligned with the FR38 rib ground line 1-2 on the ground, and the accuracy allowable deviation is 2mm. The first section main engine base center line 4-2 is aligned with the center ground line 1-5 of the port main engine base on the ground, and the allowable deviation is 2mm. Monitor the levelness of the horizontal monitoring point 4-3 of the first segment host base panel, adjust the base panel of the segment host to the horizontal, and the allowable deviation of the horizontal monitoring point 4-3 of the first segment host base panel is 3mm. After the first segment 4 is in place, tighten the spiral support head 3-1 on the support group, knock the slats 2-1 on the cement dock group, and use the segment channel steel tie rod 4-4 to connect with the pre-embedded iron 4-5 of the main group floor to ensure that the position of the first segment 4 as the positioning segment remains fixed.

[0052] S3, the second segment 5 total group, such as Figure 4As shown, check the position of support group 3 again. If the position of support group 3 is changed by collision with construction equipment, it is necessary to re-place support group 3 to the accurate position to ensure that the center position of support group 3 and the front, back, left and right deviations of the tire frame process part position point 1-3-4 are less than 20mm. Before hoisting the second segment 5, make the second segment 5FR38 rib position line 5-1 and the second segment center line 5-2 on the segment 5. According to the height position of the second segment 5, adjust the spiral support head 3-1 on the support group to the accurate position with a height deviation of 1mm. Hoist the second segment 5 into place so that the second segment 5FR38 rib position line 5-1 is aligned with the FR38 rib ground line 1-2 on the ground with an allowable accuracy deviation of 2mm. The second segment center line 5-2 is aligned with the hull center ground line 1-1 on the ground with an allowable accuracy deviation of 2mm. After positioning, the positioning constraint weld 5-4-1 between the second segment 5 and the first segment 4 is welded at a distance of 300mm from the bow and stern ends of the second segment 5. The weld length of the positioning constraint weld is 500mm. The groove between the second segment 5 and the first segment 4 is opened and polished to be smooth with a groove gap of 5 to 8mm. The weld 5-4-2 between the second segment 5 and the first segment 4 is welded. In order to avoid excessive deformation during the welding process, the welding order 5-4-3 between the second segment 5 and the first segment 4 is from the middle to the bow and stern.

[0053] S4, the third segment 6 total group, such as Figure 5As shown, check the position of cement dock group 2 and support group 3 again. If the position of cement dock group 2 and support group 3 is changed by the impact of construction equipment, it is necessary to re-place cement dock group 2 and support group 3 to the accurate position to ensure that the center position of cement dock group 2 and support group 3 and the front, back, left and right deviations of the tire frame process part position point 1-3-4 are all less than 20mm. Before hoisting the third section 6, make the third section FR38 rib position line 6-1, the third section main engine base center line 6-2, and the third section main engine base panel horizontal monitoring point 6-3 on the section 6, hoist the third section 6 into place and place it on the cement dock 2, adjust the position of the third section 6 so that the third section FR38 rib position line 6-1 is aligned with the FR38 rib ground line 1-2 on the ground, with an allowable error of 2mm, and the third section main engine base center line 6-2 is aligned with the center ground line 1-6 of the starboard main engine base on the ground, with an allowable deviation of 2mm, monitor the horizontality of the third section main engine base panel horizontal monitoring point 6-3, adjust the base panel of the main engine on the section 6 to be horizontal, and the allowable error of the third section main engine base panel horizontal monitoring point 6-3 is 3mm. After the third section 6 is in place, tighten the spiral support head 3-1 on the support group, knock tight the slats 2-1 of the cement dock pier group, and weld the positioning constraint weld 6-5-1 between the third section 6 and the second section 5 at a distance of 300mm from the bow and stern ends of the third section 6. The weld length of the positioning constraint weld is 500mm. Open the groove between the third section 6 and the second section 5, polish it smooth, and the groove gap is 5 to 8mm. Weld the weld 6-5-2 between the third section 6 and the second section 5. In order to avoid excessive deformation during the welding process, the welding order 6-5-3 between the third section 6 and the second section 5 is from the middle to the bow and stern.

[0054] S5, the fourth segment group, such as Figure 6As shown, check the position of cement dock group 2 and support group 3 again. If the position of cement dock group 2 and support group 3 is changed by the impact of construction equipment, it is necessary to re-place cement dock group 2 and support group 3 to the accurate position to ensure that the center position of cement dock group 2 and support group 3 and the front, back, left and right deviations of the tire frame process part position point 1-3-4 are all less than 20mm. Before hoisting the fourth section 7, make the fourth section FR60 rib position line 7-1, the fourth section main engine base center line 7-2, and the fourth section inner bottom plate horizontal monitoring point 7-3 on the section 7, hoist the fourth section 7 into place, place it on the cement dock 2, adjust the position of the fourth section 7, make the fourth section FR60 rib position line 7-1 and the FR60 rib ground line 1-7 on the ground aligned, the allowable error is 2mm, the fourth section main engine base center line 7-2 and the port main engine base center ground line 1-5 on the ground aligned, the allowable deviation is 2mm, monitor the levelness of the horizontal monitoring point 7-3 on the fourth section inner bottom plate, adjust the base panel of the main engine on the section 7 to be horizontal, and the fourth section inner bottom plate The horizontal monitoring point 7-3 on the support is allowed to have an error of 3mm. After the fourth segment 7 is in place, tighten the spiral support head 3-1 on the support group, tighten the slats 2-1 on the cement dock pier group, and weld the positioning constraint weld 7-4-1 between the fourth segment 7 and the first segment 4 at a distance of 300mm from the left and right ends of the fourth segment 7. The weld length of the positioning constraint weld is 500mm. Open the groove between the fourth segment 7 and the first segment 4, polish it smooth, and the groove gap is 5 to 8mm. Weld the weld 7-4-2 between the third segment 6 and the second segment 5. In order to avoid excessive deformation during welding, the welding order 7-4-3 between the fourth segment 7 and the first segment 4 is from the middle to the left and right.

[0055] S6, fifth segment 8 total group, such as Figure 7As shown, check the position of cement dock group 2 and support group 3 again. If the position of cement dock group 2 and support group 3 is changed by the impact of construction equipment, it is necessary to re-place cement dock group 2 and support group 3 to the correct position to ensure that the center position of cement dock group 2 and support group 3 and the front and rear left and right deviations of the tire frame process part position points 1-3-4 should be less than 20mm. Before the fifth segment 8 is hoisted, the fifth segment FR60 rib position line 8-1 and the fifth segment center line 8-2 are made on the segment 8. Put it in place and place it on the cement dock 2. Adjust the position of the fifth section 8 so that the FR60 rib position line 8-1 of the fifth section is aligned with the FR60 rib ground line 1-7 on the ground, with an allowable error of 2mm. The center line 8-2 of the fifth section main engine base is aligned with the center ground line 1-6 of the starboard main engine base on the ground, with an allowable deviation of 2mm. Monitor the levelness of the horizontal monitoring point 8-3 on the fifth inner bottom plate. The allowable error of the horizontal monitoring point 8-3 on the fifth section inner bottom plate is 3mm. Adjust the base panel of the main engine on the section to be horizontal. After the fifth section 8 is in place, tighten the spiral support head 3-1 on the support group, knock the slats 2-1 on the cement dock pier group, weld the positioning constraint weld 8-6-1 between the fifth section 8 and the third section 6 at 300mm from the left and right ends of the fifth section 8, and the weld length of the positioning constraint weld is 500mm. Weld the constraint plate 8-7-1 between the fifth section 8 and the fourth section 7 at 300mm from the bow and stern ends of the fifth section 8. The constraint plate 8-7-1 is welded. Double-sided continuous welding is adopted throughout, the ends should be rounded, the weld leg height is 0.7 times the plate thickness, the weld leg height at the corner is 0.8 times the plate thickness, the groove between the fifth section 8 and the third section 6 is opened, polished and smooth, the groove gap is 5 to 8 mm, the weld 8-6-2 between the fifth section 8 and the third section 6 is welded, in order to avoid excessive deformation during the welding process, the welding order 8-6-3 between the fifth section 8 and the third section 6 is from the middle to the left and right.

[0056] S7, set the bottom section of the cabin to carry the tire frame, such as Figure 8As shown, a hull center ground line 9-1 of the dock area is opened on the floor of the dock, and a FR40 rib position ground line 9-2 of the dock area is opened according to the hull center ground line 9-1. The verticality of the dock hull center ground line 9-1 and the FR40 rib position ground line 9-2 of the dock area is controlled at 2mm. A group of longitudinal section lines 9-3 of the dock area are opened according to the hull center ground line 9-1, and the parallelism is controlled at 2mm. A group of rib position ground lines 9-4 of the dock area are opened according to the FR40 rib position ground line 9-2 of the dock area, and the parallelism is controlled at 2mm. A group of dock pier position marks 9-6-1 are opened according to a group of longitudinal section lines 9-3 of the dock area and the FR40 rib position ground line 9-2 of the dock area. The dock pier position mark 9-6-1 should be strictly set according to the rib position, and the deviation of the front, back, left and right is less than 20mm, and finally the dock ground line 9 of the bottom section of the engine room of the LNG ship is formed, as shown in FIG. Fig. 9 As shown, according to the intersection of a group of rib position ground lines 9-4 in the dock area and a group of longitudinal section lines 9-3 in the dock area, a group of dock supports 9-5 are arranged, and the front, rear, left, and right deviations of a group of dock supports 9-5 are required to be less than 20mm. According to a group of dock pier position marks 9-6-1, a group of dock piers 9-6 are arranged, and the front, rear, left, and right deviations of a group of dock piers 9-6 are less than 20mm.

[0057] S8, engine room bottom section dock loading, such as Fig.10 As shown, check the positions of a set of dock supports 9-5 and a set of dock piers 9-6 again, and the deviations are less than 30mm. Before hoisting on the engine room bottom section 10, make sure the center line 10-1 of the engine room bottom section, the FR40 rib position line 10-2 of the engine room bottom section, the horizontal monitoring point 10-3 on the inner bottom plate of the engine room bottom section, set up four shaft system benchmarks 10-4 at the bow and stern on the engine room bottom section 10, and make sure the center line of the shaft system at the position L0 from the inner bottom plate. 10-4-1, make a hull baseline 10-4-2 on a set of dock piers 9-6, hoist the engine room bottom section 10 in place, so that the distance between the axis centerline 10-4-1 and the hull baseline 10-4-2 is L1, the allowable deviation range is 0-2mm, the section hull centerline 10-1 is aligned with the dock bottom hull centerline 9-1, the engine room bottom section FR40 rib position line 10-2 is aligned with the dock bottom FR40 rib position ground line 9-2, and the deviation is less than 2mm. Monitor the horizontality of the horizontal monitoring point 10-3 on the bottom plate of the engine room bottom section, and the allowable deviation of the horizontal monitoring point 10-3 on the bottom plate of the engine room bottom section is less than 4mm. After loading is completed, the section channel steel tie rod 10-4 is connected to the pre-embedded iron 10-5 of the dock floor to complete the loading of the engine room bottom section 10.

[0058] The above describes the specific embodiments of the present invention, but those skilled in the art should understand that these are only examples, and various changes or modifications can be made to these embodiments without departing from the principles and essence of the present invention. The above embodiments are only illustrative of the technical principles and effects of the present invention, and are not intended to limit the protection of the rights of the present invention.

Claims

1. A method for assembling a bottom section of an LNG ship engine room, wherein the bottom section of the engine room on the LNG ship comprises a first section, a second section, a third section, a fourth section and a fifth section, wherein the first section and the third section are symmetrically distributed on both sides of the second section, and the middle of the rear side of the second section is spliced ​​with the fourth section and the fifth section respectively, and the fourth section and the fifth section are arranged symmetrically, characterized in that: The method firstly manufactures the first segment, the second segment, the third segment, the fourth segment and the fifth segment respectively, then performs marking positioning and tire frame arrangement, then hoists, welds and assembles the first segment, the second segment, the third segment, the fourth segment and the fifth segment one by one, assembles the five segments to form a cabin bottom layer segment, and then carries the assembled cabin bottom layer segment on a ship dock. The method specifically comprises the following steps: S1, set up the general assembly cradle of the engine room bottom section, first mark the line on the general assembly platform, mark the center ground line of the hull, the FR38 rib ground line is based on the hull center ground line to make the cradle longitudinal section ground line group, and then make the rib position ground line group according to the FR38 rib ground line. The intersection of the cradle longitudinal section ground line group and the rib position ground line group is the cradle process part position point. After the ground line survey is completed, the general assembly cradle ground line of the LNG ship engine room bottom section is formed; the cement dock pier group and the support group are arranged according to the cradle process part position point; according to the hull center ground line, mark the center ground line of the port main engine base and the center ground line of the starboard main engine base, and according to the FR38 rib ground line, mark another FR60 rib ground line; S2, positioning the first segment. After the first segment is hoisted into place, tighten the spiral support head on the support group, knock the slats on the cement dock pier group, and use the segmented channel steel tie rods to connect with the pre-buried iron of the main group floor; S3, second segment assembly, according to the height position of the second segment, hoist the second segment into place, after positioning, weld the second segment and the first segment at the bow and stern ends of the second segment, the welding order is from the middle to the bow and stern direction; S4, the third section assembly, after the third section is hoisted into place, tighten the spiral support head on the support group, knock the slats of the cement dock pier group, and weld the positioning restraint weld between the third section and the second section at the bow and stern ends of the third section. The welding order is from the middle to the bow and stern direction; S5, the fourth section assembly, after the fourth section is hoisted into place, tighten the spiral support head on the support group, knock the slats on the cement dock pier group, and weld the positioning constraint weld between the fourth section and the first section at the left and right ends of the fourth section. The welding order is from the middle to the left and right directions; S6, the fifth section assembly, after the fifth section is hoisted into place, tighten the spiral support head on the support group, knock the slats on the cement dock pier group, weld the positioning constraint weld between the fifth section and the third section at the left and right ends of the fifth section, weld the constraint plate between the fifth section and the fourth section at the bow and stern ends of the fifth section, all welding adopts double-sided continuous welding, the ends should be angled, the height of the weld leg is 0.7 times the plate thickness, the height of the weld leg at the angle is 0.8 times the plate thickness, and the order of welding is from the middle to the left and right directions; S7, set up a cradle for the engine room bottom section, open a hull center ground line of the dock area on the dock floor, open a FR40 rib ground line out of the dock area according to the hull center ground line, open a group of longitudinal sections out of the dock area according to the hull center ground line, open a group of rib ground lines out of the dock area according to the FR40 rib ground line of the dock area, open a group of dock pier position marks according to a group of longitudinal sections in the dock area and the FR40 rib ground line of the dock area, form a dock ground line for the bottom section of the LNG ship engine room, set up a group of dock supports according to the intersection of a group of rib ground lines in the dock area and a group of longitudinal sections in the dock area, and arrange a group of dock piers according to the position marks of a group of dock piers; S8, the engine room bottom section is docked. Four shaft system benchmarks are set up on the engine room bottom section. The shaft system centerline is made at a distance of L0 from the inner bottom plate. The hull baseline is made on a set of dock piers. The engine room bottom section is hoisted into place so that the distance between the shaft system centerline and the hull baseline is L1. The hull centerline of the section is aligned with the hull centerline of the dock bottom. The FR40 rib position line of the engine room bottom section is aligned with the FR40 rib position ground line of the dock bottom. The section channel steel tie rod is used to connect with the embedded iron of the dock floor to complete the loading of the engine room bottom section.

2. The method for assembling the bottom section of the engine room of an LNG carrier according to claim 1 is characterized in that: In the step S1, the straightness deviation of the hull center ground line and the FR38 rib ground line is 1mm, and the verticality deviation is 1mm; the straightness deviation of the tire frame longitudinal section ground line group and the rib ground line group is 2mm, and the verticality deviation is 2mm; the parallelism error between the hull center ground line and the center ground line of the port main engine base and the center ground line of the starboard main engine base is 1mm, the parallelism error between the FR38 rib ground line and the FR60 rib ground line is 1mm, and the verticality error between the FR38 rib ground line, the FR60 rib ground line, the hull center ground line, the port main engine base center ground line, and the starboard main engine base center ground line is less than 2mm.

3. The method for assembling the bottom section of the engine room of an LNG carrier according to claim 1 is characterized in that: In the steps S2-S6, the cement dock group and the support group are arranged according to the position point of the tire frame process part. The front, back, left and right deviations of the center positions of the cement dock group and the support group and the position point of the tire frame process part should be less than 20 mm. In the steps S1-S6, before hoisting each segment, the segment FR38 rib position line, each segment center line, and the horizontal monitoring point of the segment host base panel are made on each segment. After the segment is hoisted, the horizontality of the horizontal monitoring points of the segment host base panel is monitored, and the base panel of the host on the segment is adjusted to be horizontal. The horizontal monitoring points of the segment host base panel are allowed to deviate by less than 3 mm.

4. The method for assembling the bottom section of the engine room of an LNG carrier according to claim 1 is characterized in that: In the steps S2-S6, the position of each segment is adjusted so that the segment FR38 rib position line is aligned with the FR38 rib ground line on the ground, with an allowable accuracy deviation of less than 2 mm, and the center line of each segment main engine base is aligned with the center ground line of the port main engine base on the ground, with an allowable deviation of less than 2 mm.

5. The method for assembling the bottom section of the engine room of an LNG carrier according to claim 1, characterized in that: After the segment positioning is completed in step S3, a positioning restraint weld is welded between the second segment and the first segment at a distance of 300 mm from the bow and stern ends of the second segment. The weld length of the positioning restraint weld is 490-510 mm. A groove is opened between the second segment and the first segment, and the groove gap is 5-8 mm.

6. The method for assembling the bottom section of the engine room of an LNG carrier according to claim 1, characterized in that: In step S4, a positioning restraint weld is welded between the third segment and the second segment at a distance of 300 mm from the bow and stern ends of the third segment, the weld length of the positioning restraint weld is 490-510 mm, and a groove is opened between the third segment and the second segment, and the groove gap is 5-8 mm.

7. The method for assembling the bottom section of the engine room of an LNG carrier according to claim 1, characterized in that: In step S5, a positioning restraint weld is welded between the fourth segment and the first segment at a distance of 300 mm from the left and right ends of the fourth segment, the weld length of the positioning restraint weld is 490-510 mm, and a groove is opened between the fourth segment and the first segment, and the groove gap is 5-8 mm.

8. The method for assembling the bottom section of the engine room of an LNG carrier according to claim 1, characterized in that: In the step S6, a positioning restraint weld is welded between the fifth segment and the third segment at a distance of 300 mm from the left and right ends of the fifth segment, and the weld length of the positioning restraint weld is 490-510 mm. A restraint plate is welded between the fifth segment and the fourth segment at a distance of 300 mm from the bow and stern ends of the fifth segment, and a groove is formed on the restraint plate between the fifth segment and the third segment, and a groove gap is 5-8 mm.

9. The method for assembling the bottom section of the engine room of an LNG carrier according to claim 1, characterized in that: In the step S7, the verticality between the center ground line of the dock hull and the FR40 rib ground line of the dock area is controlled at 2 mm, a group of dock supports are set according to the intersection of a group of rib ground lines in the dock area and a group of longitudinal sections in the dock area, and the front, rear, left, and right deviations of a group of dock supports are all less than 20 mm, and a group of dock piers are arranged according to the position marks of a group of dock piers, and the front, rear, left, and right deviations of a group of dock piers are less than 20 mm.

10. The method for assembling the bottom section of the engine room of an LNG carrier according to claim 1, characterized in that: In the step S8, the positions of a group of dock supports and a group of dock piers have a front, rear, left and right deviation of less than 30 mm, the bottom section of the engine room is hoisted into place, so that the distance between the center line of the shaft system and the baseline of the hull is L1, the allowable deviation range is 0-2 mm, the center line of the hull of the section is aligned with the center line of the hull of the dock bottom, the FR40 rib position line on the bottom section of the engine room is aligned with the FR40 rib position ground line of the dock bottom, the deviation is less than 2 mm, the horizontality of the horizontal monitoring points on the bottom plate of the bottom section of the engine room is monitored, and the allowable deviation of the horizontal monitoring points on the bottom plate of the bottom section of the engine room is less than 4 mm.

11. A bottom section of the engine room of an LNG carrier, characterized in that: The bottom section of the engine room of the LNG carrier is assembled and loaded by the loading method described in any one of claims 1-10.

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