A sectional division and general assembly method for the bottom of an LNG ship

Abstract

The present invention relates to a sectional division and general assembly method for the bottom of an LNG ship, comprising the following steps: Step 1, transversely divide the bottom of the LNG ship into three sections, namely the left section, the middle section, and the right section; Step 2, respectively conduct longitudinal general assembly on the left and right sections, and erect scaffolding on the inner bottom plates of the left and right sections; Step 3, conduct longitudinal general assembly on the middle section, and after completing the pre-assembly of the overall section integrity, hoist the overall section into the dry dock. The sectional division and general assembly method for the bottom of an LNG ship according to the present invention can effectively reduce the load of the gantry crane, improve the integrity of the overall section, thereby shortening the shipyard construction period and reducing the shipyard construction cost.

Description

Technical Field

[0001] The present invention relates to the field of shipbuilding, and specifically relates to a sectional division and general assembly method for the bottom of an LNG ship. Background Art

[0002] The dock has always been the core resource of the shipyard. How to improve the utilization rate of the dock general assembly site, improve the outfitting integrity of the general section, and reduce the number of gantry crane lifts is the only way to shorten the dock cycle, reduce the shipbuilding man-hours and costs. At present, in the manufacturing process of LNG ships in China, the dock cycle takes 5 - 6 months, and the outfitting integrity when leaving the dock is only about 60%. There are problems such as insufficient general assembly site, incomplete pre-outfitting of the bottom general section, the scaffolding erection occupying the general assembly site, and excessive use of gantry cranes for lifting.

[0003] The prior art CN113895586A discloses a sectional division method for the cargo hold area of a thin-film type LNG ship. The method includes the following steps: 1) All key nodes W1 - W5 on the inner shell wall of the cargo hold are drawn within the section; 2) The large joint between two cargo hold areas is arranged in the transverse bulkhead; 3) Each transverse bulkhead is independently divided; 4) The liquid dome area is divided into an independent section. This sectional division method not only ensures the construction accuracy of the cargo hold volume and the structural alignment accuracy of key nodes, but also can reduce the dock erection and lifting, reduce the welding and painting damage of the large joints in the dock, maximize the forward movement of the dock and quay outfitting work, improve the ship launching integrity, and further shorten the dock cycle. However, it only discloses the sectional division method for the cargo hold area and does not solve the problems of insufficient general assembly site, incomplete pre-outfitting of the bottom general section, the scaffolding erection occupying the general assembly site, and excessive use of gantry cranes for lifting. Summary of the Invention

[0004] To solve the technical problems existing in the prior art, the present invention provides a sectional division and general assembly method for the bottom of an LNG ship, which can effectively reduce the gantry crane load, improve the integrity of the general section, thereby shortening the dock construction cycle and reducing the dock construction cost.

[0005] To achieve the above object, the technical solution of the present invention is as follows:

[0006] A sectional division and general assembly method for the bottom of an LNG ship, the method includes the following steps:

[0007] Step 1, horizontally divide the bottom of the LNG ship into three sections, namely the left section, the middle section, and the right section;

[0008] Step 2, longitudinally assemble the left and right sections respectively to obtain the left and right general sections, and erect a left scaffolding module and a right scaffolding module on the inner bottom plates of the left and right sections respectively;

[0009] Step 3: Vertically assemble the intermediate subsections to obtain the intermediate main section. After completing the pre-assembly of the integrity of the main section, lift and install the main section into the dry dock.

[0010] As a preferred technical solution, in Step 1, the steps of horizontally dividing the bottom of the LNG ship into three sections include: determining the length, width, and weight limits of the subsections at the bottom of the LNG ship, estimating the weight distribution of the bottom structure of the LNG ship in combination with the layout of the scaffolding, estimating the weight of the outfitting parts in the intermediate pipe tunnel at the bottom of the LNG ship, and horizontally dividing the bottom of the LNG ship into three sections according to the lifting weight limit conditions of the dock gantry crane.

[0011] As a preferred technical solution, in Step 2, the steps of erecting the left and right scaffolding modules on the inner bottom plates of the left and right subsections respectively include: drawing the grid lines for the layout of the scaffolding bases on the inner bottom plates of the left and right subsections; erecting the left and right scaffolding modules; fixing the left scaffolding module to the left subsection and the right scaffolding module to the right subsection.

[0012] As a preferred technical solution, the scaffolding is fixed to the bottom subsection through tie rods, and the two ends of the tie rods are respectively connected to the columns of the scaffolding and the inner wall plate of the side shell through bolts.

[0013] As a preferred technical solution, in Step 3, the steps of longitudinally assembling the intermediate subsections include performing structural assembly, welding, and weld grinding on the intermediate subsections; connecting the pipes in the pipe tunnel and completing the outfitting of the outfitting parts embedded in the pipe tunnel; repairing the welds and damaged paint.

[0014] As a preferred technical solution, in Step 3, the steps of lifting and installing the main section into the dry dock include: lifting the intermediate main section into the ship dry dock; lifting the left and right main sections into the dry dock and closing them with the intermediate main section; drawing the grid lines for the layout of the scaffolding bases in the middle of the large hold on the inner bottom plate of the intermediate main section; lifting the middle scaffolding module into the dry dock and connecting the middle scaffolding module with the left and right scaffolding modules.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0016] (1) The method for subsection division and overall assembly of the bottom of an LNG ship according to the present invention realizes the overall assembly of the scaffolding and the bottom subsection through subsection division and optimized overall assembly methods, which not only saves the number of lifting operations for overall assembly of the subsections by the gantry crane, reduces the requirement for the overall assembly site for scaffolding erection, reduces the number of times of lifting the scaffolding by the gantry crane, but also shortens the overall assembly cycle, saves the overall assembly site, and improves the utilization efficiency of the overall assembly site.

[0017] (2) The method for subsection division and overall assembly of the bottom of an LNG ship according to the present invention divides the pipe tunnel subsection into one subsection through the subsection division method, which not only improves the integrity of subsection pre-outfitting, but also maximizes the overall assembly integrity, thereby effectively reducing the workload of dry dock operations. Description of the Drawings

[0018] Figure 1 It is a schematic cross-sectional view of the block division and staging method for the bottom of an LNG ship according to the present invention, showing the block and scaffolding division.

[0019] Figure 2 It is a top view of the bottom block division and the grid line layout of the scaffolding base in the block division and staging method for the bottom of an LNG ship according to the present invention.

[0020] Figure 3 It is a schematic connection diagram of the left and right blocks and the scaffolding in the block division and staging method for the bottom of an LNG ship according to the present invention.

[0021] Figure 4 It is a schematic diagram of hoisting the bottom block into the dry dock in the block division and staging method for the bottom of an LNG ship according to the present invention.

[0022] In the figure: 1. Left block; 2. Middle block; 3. Right block; 4. Left scaffolding module; 5. Middle scaffolding module; 6. Right scaffolding module; 7. Grid line; 8. Scaffolding base; 9. Tie rod. Detailed Embodiment

[0023] The technical solution of the present invention will be further described below in conjunction with the detailed embodiment:

[0024] A method for block division and staging of the bottom of an LNG ship, the method comprising the following steps:

[0025] As Figure 1 shown, in step one, determine the limiting conditions of the manufacturing site for the blocks at the bottom of the LNG ship, namely the length, width and weight limits, combine with the layout of the scaffolding, estimate the weight distribution of the bottom structure of the LNG ship, estimate the weight of the outfitting parts in the intermediate pipe tunnel at the bottom of the LNG ship, and horizontally divide the bottom of the LNG ship into three sections according to the requirements of pre-outfitting integrity and the lifting weight limit condition of the dock gantry crane. The three sections are the left block 1, the middle block 2 and the right block 3 respectively;

[0026] In this embodiment, the limiting conditions of the block manufacturing site are specifically that the maximum size of the flat block is 21 m × 21 m in length and width, the maximum tonnage of the largest segment is 220 tons, and the maximum total tonnage of the block is 300 tons. The maximum tonnage in the curved inner field is 160 tons, and the maximum tonnage for outfitting in the outer field is 400 tons. The lifting capacity of the dock gantry crane is 700 tons for two units, and 960 tons for two units lifting together. The lifting weight limit condition of the dock gantry crane is that the left block 1 and the right block 3 at the bottom, including the outfitting parts, are below 250 tons, the estimated weight of the scaffolding erected on the inner bottom plate is below 120 tons, the bottom middle block 2 is below 280 tons, and the final total weight of the left, middle and right blocks is controlled below 900 tons.

[0027] As Figure 2 shown, in step two, longitudinally assemble the left section 1 and the right section 3 respectively to obtain the left and right overall sections. On the inner bottom plates of the left section 1 and the right section 3, erect the left scaffolding module 4 and the right scaffolding module 6 respectively. Specifically, draw the grid lines 7 for arranging the scaffolding bases 8 on the inner bottom plates of the left section 1 and the right section 3; erect the left scaffolding module 4 and the right scaffolding module 6. To reduce the scaffolding erection period, the left scaffolding module 4 and the right scaffolding module 6 can also be divided into small pieces, pre-erected externally and then hoisted onto the inner bottom plate and assembled together; fix the left scaffolding module 4 to the left section 1 and fix the right scaffolding module 6 to the right section 3 to prevent the left scaffolding module 4 and the right scaffolding module 6 from tipping over when the overall section enters the dry dock. Both ends of the tie rod 9 are respectively connected to the columns of the scaffolding and the side inner wall plates through bolts to facilitate the quick removal of the tie rod 9;

[0028] As Figure 3 and Figure 4 shown, in step three, longitudinally assemble the middle section 2 to obtain the middle overall section, and perform structural assembly, welding and weld grinding on the middle overall section; connect the pipes in the pipe tunnel and complete the outfitting of the outfitting parts embedded in the pipe tunnel; repair the welds and damaged paint. After the overall assembly of the left section 1, the middle section 2 and the right section 3 is completed, hoist the overall section into the dry dock. Specifically, first hoist the middle overall section into the shipyard dry dock; then hoist the left and right overall sections into the dry dock and close them with the middle overall section; draw the grid lines 7 for arranging the scaffolding bases 8 in the middle of the large cabin on the inner bottom plate of the middle overall section; then hoist the middle scaffolding module 5 into the dry dock, and finally connect the middle scaffolding module 5 with the left scaffolding module 4 and the right scaffolding module 6. In this way, the rapid forming of the bottom of the LNG ship is completed, ensuring the integrity requirements of the bottom pre-installation, and at the same time, the rapid erection of the scaffolding for the large cabin part is completed.

[0029] This embodiment is only a further explanation of the present invention and not a limitation thereof. Those skilled in the art can make non-creative modifications to this embodiment as needed after reading this specification, but as long as it is within the scope of the claims of the present invention, it is protected by the patent law.

Claims

1. A sectional division and general assembly method for the bottom of an LNG ship, characterized in that, The method includes the following steps: Step 1: Horizontally divide the bottom of the LNG ship into three sections, namely the left section, the middle section, and the right section. The step of horizontally dividing the bottom of the LNG ship into three sections includes: determining the length, width, and weight limits of the sections at the bottom of the LNG ship, estimating the weight distribution of the bottom structure of the LNG ship in combination with the arrangement of the scaffolding, estimating the weight of the outfitting parts in the pipe tunnel in the middle of the bottom of the LNG ship, and horizontally dividing the bottom of the LNG ship into three sections according to the lifting weight limit condition of the dock gantry crane; Step 2: Vertically pre-assemble the left and right sections respectively to obtain the left and right sub-assemblies, and erect a left scaffolding module and a right scaffolding module on the inner bottom plates of the left and right sections respectively; Step 3: Vertically pre-assemble the middle section to obtain the middle sub-assembly, and after completing the integrity pre-installation of the sub-assembly, hoist the sub-assembly into the dock; The step of vertically pre-assembling the middle section includes structural assembly, welding, and weld grinding of the middle section; connecting the pipes in the pipe tunnel and completely outfitting the outfitting parts embedded in the pipe tunnel; repairing the welds and damaged paint; The step of hoisting the sub-assembly into the dock includes: hoisting the middle sub-assembly into the shipyard dock; hoisting the left and right sub-assemblies into the dock and joining them with the middle sub-assembly; marking the grid lines for the layout of the scaffolding base in the middle of the large cargo hold on the inner bottom plate of the middle sub-assembly; hoisting the middle scaffolding module into the dock and connecting the middle scaffolding module with the left scaffolding module and the right scaffolding module.

2. The sectional division and general assembly method for the bottom of an LNG ship according to claim 1, characterized in that, In Step 2, erecting the left and right scaffolding modules on the inner bottom plates of the left and right sections respectively includes the following steps: marking the grid lines for the layout of the scaffolding base on the inner bottom plates of the left and right sections; erecting the left and right scaffolding modules; fixing the left scaffolding module to the left section and fixing the right scaffolding module to the right section.

3. The sectional division and general assembly method for the bottom of an LNG ship according to claim 2, characterized in that The scaffolding is fixed to the bottom section through tie rods, and both ends of the tie rods are connected to the columns of the scaffolding and the inner side wall plates of the hull through bolts.

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