Hole opening method for cargo hold broadside process hole of LNG (Liquefied Natural Gas) ship

Abstract

The invention discloses an LNG (Liquefied Natural Gas) ship cargo hold broadside process hole opening method which sequentially comprises the following steps: in a design stage, stripping a process hole small section from a broadside section, and nesting components of the process hole small section and the broadside section; auxiliary hole small sections and broadside sections are built on the same jig frame; stripping a small segment of the process hole from a broadside segment, and transporting and coating the two segments on an upper portal frame; and the auxiliary hole small sections are embedded into the broadside main ship body and are folded and welded. According to the method, the situation that holes are formed in the complete broadside sections is avoided, the time for working aloft and occupying a jig frame is shortened, the platform resource utilization rate and the working efficiency are improved, and the ship building time is shortened.

Description

Technical Field

[0001] This invention relates to the field of shipbuilding technology, and in particular to a method for opening process holes on the side of the cargo hold of an LNG ship. Background Technology

[0002] In LNG carrier construction, the installation of cargo hold containment systems is typically scheduled after the main structure is completed. However, because the installation of containment systems (such as membrane-type or MARK III type) requires a large amount of materials and equipment to move in and out of the cargo hold, it is necessary to establish communication between the inside and outside of the hold through process openings. The traditional construction method involves workers manually marking and cutting process openings on-site after the platform side assembly is completed in sections. However, this manual operation has many drawbacks: First, the precision of manual cutting is difficult to guarantee, resulting in poor cut quality and issues such as burrs and irregular edges, which affect the welding quality of subsequent enclosure system plates. Second, uneven heat input during cutting can easily lead to localized deformation of the steel plate, increasing the amount of additional straightening work and potentially affecting the airtightness requirements of the cargo hold. Furthermore, process openings are usually located high on the side of the hull, making high-altitude operations not only difficult and fraught with safety hazards but also inefficient, further extending the overall assembly cycle.

[0003] More importantly, this inefficient construction method occupies the main assembly frame resources for a long time, affecting the subsequent installation and transfer of segments, resulting in a decrease in platform resource utilization and slowing down the overall construction progress. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this application provides a method for opening process holes on the side of LNG ship cargo holds, thereby solving the technical problems of existing technologies that require on-site cutting of process holes on the side of LNG ship cargo holds, which affects the welding quality of subsequent enclosure system plates, increases additional straightening work, and occupies a long time in the assembly jig.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution: A method for opening process holes on the side of a cargo hold in an LNG carrier includes the following steps; S1. During the design phase, the process holes on the side are separated from the side sections in the form of small segments to form small process hole segments, and the components of the process hole segments and the side sections are nested. S2, the same jig construction process for small-section holes and side sections; S3, the process hole segments are peeled off from the side of the ship and transported and painted on the gantry separately.

[0006] S4. The process hole section is delivered directly to the dock. After the cargo hold containment system is completed, the process hole section is embedded into the side hull, and the process hole section and the side section are welded together.

[0007] In one embodiment, the process hole segment includes a second outer plate and a second inner shell plate, and the side segment includes a first outer plate and a first inner shell plate. The second outer plate and the second inner shell plate are connected to each other and the first outer plate and the first inner shell plate are connected by a connecting platform. The inner surfaces of the second outer plate, the second inner shell plate, the first outer plate, and the first inner shell plate are all provided with longitudinal ribs.

[0008] In one implementation, in step S1, the first outer plate and the first inner shell plate are first fitted together, and then the second outer plate is cut out by making holes in the first outer plate according to the design position and size. The second inner shell plate is cut out by making holes in the first inner shell plate according to the design position and size. A break is set on the connecting member between the process hole section and the side section to disconnect the longitudinal ribs adjacent to the process hole section and the side section 1.

[0009] In one embodiment, when the first outer plate is cut into the second outer plate in step S1, a bridge is provided between the first outer plate and the second outer plate; when the first inner shell plate is cut into the second inner shell plate, a bridge is provided between the first inner shell plate and the second inner shell plate.

[0010] In one embodiment, the bridges on the outer periphery of the second outer plate and the outer periphery of the second inner shell plate are symmetrically arranged, and the width of the bridge is 90-120mm. The first outer plate and the first inner shell plate are cut by CNC.

[0011] In one implementation, step S3 specifically includes disconnecting the bridge, lifting the process hole segment from the side segment, turning the process hole segment 180° and using the second outer plate as the base for gantry coating, and turning the side segment 180° in the same way and using the first outer plate as the base for gantry coating.

[0012] In one implementation, in step S2, the inner shell middle group and the outer shell middle group are first assembled using the first outer shell plate and the first inner shell plate as base surfaces, respectively. Then, using the inner shell middle group as base surface, the outer shell middle group is flipped 180° so that the outer shell middle group and the inner shell middle group are joined and welded together to form a side section with embedded process hole segments. The outer shell middle group includes a small outer shell middle group, which is a small process hole segment that does not include the second inner shell plate.

[0013] In one embodiment, in step S2, after the inner shell middle group and the outer plate middle group are assembled and before the outer plate middle group is turned over, the longitudinal bones at the adjacent points of the process hole small segment and the side segment are fixedly connected by the horse plate.

[0014] In one embodiment, after the outer plate assembly and the inner shell assembly are joined together, a reinforcing member is provided at the joint to connect the second outer plate and the second inner shell plate. The reinforcing member is removed after S4.

[0015] In one embodiment, the opening size of the first outer plate is larger than the opening size of the first inner shell plate, the process hole segments are wedge-shaped, and the size of the second outer plate is larger than that of the second inner shell plate.

[0016] Compared with the prior art, this application has at least the following beneficial effects: This application separates the process hole segments from the side sections during the design phase and directly nests the process hole segments and components of the side sections, thereby avoiding drilling holes in the complete side sections, reducing high-altitude operations and time spent on jigs, improving platform resource utilization and work efficiency, and shortening ship construction time. This application also ensures welding precision and the quality of the side sections through CNC cutting of the outer and inner hull plates. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the side section with embedded process holes in an embodiment of this application; Figure 2 This is a schematic diagram showing the construction of the process hole section and the side section using the same jig in the embodiments of this application; Figure 3 This is a schematic diagram showing the connection between the small process hole section and the side section via a bridge in an embodiment of this application; Figure 4 This is a sectional view of the side section in an embodiment of this application; Figure 5 This is a schematic diagram of the structure in this application embodiment where the longitudinal bones are fixedly connected by a horse plate.

[0018] Reference numerals: 1. Side section; 2. Small section of process hole; 201. Second outer plate; 202. Second inner shell plate; 3. Inner shell middle assembly; 4. Outer plate middle assembly; 5. Small outer plate middle assembly; 6. Bridge; 7. First outer plate; 8. First inner shell plate; 9. Connecting platform; 10. Longitudinal rib; 11. Inner shell plate opening; 12. Outer plate opening; 13. Horse plate. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the invention is described below with reference to specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0020] The terminology used in this disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. The singular forms “a,” “the,” and “the” as used in this disclosure and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any and all possible combinations of one or more of the associated listed items.

[0021] It should be understood that although the terms first, second, third, etc., may be used in this disclosure to describe various information, such information should not be limited to these terms and should not be construed as indicating or implying relative importance. These terms are used only to distinguish information of the same type from one another. For example, without departing from the scope of this disclosure, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to determination."

[0022] In the description of this invention, unless otherwise specified and limited, it should be noted that the terms "installation", "connection" and "linking" should be interpreted broadly. For example, they can refer to mechanical connection or internal connection between two components. They can be direct connection or indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0023] To better understand the technical solution of the present invention, the present invention will be described in detail below with reference to specific embodiments and accompanying drawings.

[0024] This embodiment provides a method for opening process holes on the side of the cargo hold of an LNG ship, such as... Figures 1-5 As shown, it includes the following steps: S1, During the design phase, the process holes on the side are separated from the side section 1 in the form of small segments to form process hole small segments 2, and the components of process hole small segments 2 and side section 1 are nested. S2, the same frame construction process hole small segment 2 and side segment 1; S3, peel the process hole section 2 from the side section 1 and transport and paint it on the gantry respectively.

[0025] S4. The process hole section 2 is delivered directly to the dock. After the cargo hold enclosure system is completed, the process hole section 2 is embedded into the side hull of the ship, and the process hole section 2 and the side section 1 are welded together.

[0026] The process hole segment 2 includes a second outer plate 201 and a second inner shell plate 202. The side segment 1 includes a first outer plate 7 and a first inner shell plate 8. The second outer plate 201 and the second inner shell plate 202, as well as the first outer plate 7 and the first inner shell plate 8, are connected by a connecting platform 9. The inner surfaces of the second outer plate 201, the second inner shell plate 202, the first outer plate 7, and the first inner shell plate 8 are all provided with longitudinal ribs 10. In this embodiment, in step S1, the first outer plate 7 and the first inner shell plate 8 are first fitted together. Then, holes are drilled on the first outer plate 7 according to the designed position and size to cut out the second outer plate 201. Holes are drilled on the first inner shell plate 8 according to the designed position and size to cut out the second inner shell plate 202. A break is set on the connecting member between the process hole segment 2 and the side segment 1 to disconnect the longitudinal ribs 10 at the adjacent points of the process hole segment 2 and the side segment 1. The connecting member includes a connecting platform 9 and a rib.

[0027] To facilitate the simultaneous construction of the small process section 2 and the side section 1 using the same mold, and to reduce site support, a bridge 6 is provided between the first outer plate 7 and the second outer plate 201 when the first outer plate 7 is cut out in step S1, and a bridge 6 is provided between the first inner shell plate 8 and the second inner shell plate 202 when the first inner shell plate 8 is cut out. The bridges 6 on the outer periphery of the second outer plate 201 and the second inner shell plate 202 are symmetrically arranged. In this embodiment, the width of the bridge 6 is 90-120mm. In this embodiment, CNC cutting of the first outer plate 7 and the first inner shell plate 8 is used.

[0028] In step S2, the inner shell middle assembly 3 and the outer shell middle assembly 4 are first assembled using the first outer shell 7 and the first inner shell 8 as base surfaces, respectively. Then, using the inner shell middle assembly 3 as the base surface, the outer shell middle assembly 4 is flipped 180° so that the outer shell middle assembly 4 and the inner shell middle assembly 3 are joined and welded together to form the side section 1 with the embedded process hole small segment 2. The outer shell middle assembly 4 includes a small outer shell middle assembly 5, which is the process hole small segment 2 of 202 that does not include the second inner shell 2. In this embodiment, after the inner shell middle assembly 3 and the outer shell middle assembly 4 are assembled, before flipping the outer shell middle assembly 4, the longitudinal ribs 10 at the adjacent positions of the process hole small segment 2 and the side section 1 are fixedly connected by a rib plate 13, thereby fixing the longitudinal ribs when the outer shell middle assembly 4 is flipped.

[0029] Step S2 further includes: after the outer plate middle assembly 4 and the inner shell middle assembly 3 are joined, a reinforcing member is provided at the joint to connect the second outer plate and the second inner shell plate, so as to avoid deformation of the connecting components. In this embodiment, the reinforcing member is a channel steel parallel to the connecting platform 9. The reinforcing member is removed after the welding process hole small segment 2 and the side segment 1 are joined in S4.

[0030] Step S3 specifically includes disconnecting the bridge 6, lifting the process hole segment 2 from the side segment 1, turning it 180° and using the second outer plate 201 as the base for the gantry coating, and turning the side segment 1 180° in the same way and using the first outer plate as the base for the gantry coating.

[0031] In this embodiment, the opening size of the first outer plate 7 is larger than the opening size of the first inner shell plate 8, the process hole segment 2 is wedge-shaped, and the size of the second outer plate 7 is larger than that of the second inner shell plate 202, so as to facilitate the subsequent embedding of the process hole segment 2 into the side segment 1.

[0032] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them; although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of the invention or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the technical solutions claimed in the present invention.

Claims

1. A method for opening process holes on the side of a cargo hold in an LNG carrier, characterized in that, Includes the following steps; S1. During the design phase, the process holes on the side are separated from the side sections in the form of small segments to form small process hole segments, and the components of the process hole segments and the side sections are nested. S2, the same jig construction process for small-section holes and side sections; S3, peel off the small process hole sections from the side of the hull and transport them separately on the gantry for painting; S4. The process hole section is delivered directly to the dock. After the cargo hold containment system is completed, the process hole section is embedded into the side hull, and the process hole section and the side section are welded together.

2. The mounting method according to claim 1, characterized in that, The process hole segment includes a second outer plate and a second inner shell plate, and the side segment includes a first outer plate and a first inner shell plate. The second outer plate and the second inner shell plate are connected to each other and the first outer plate and the first inner shell plate are connected by a connecting platform. The inner surfaces of the second outer plate, the second inner shell plate, the first outer plate, and the first inner shell plate are all provided with longitudinal ribs.

3. The mounting method according to claim 2, characterized in that, In step S1, the first outer plate and the first inner shell plate are first fitted together. Then, the second outer plate is cut out by making holes in the first outer plate according to the design position and size. The second inner shell plate is cut out by making holes in the first inner shell plate according to the design position and size. A break is set on the connecting member between the process hole section and the side section to disconnect the longitudinal ribs adjacent to the process hole section and the side section 1.

4. The mounting method according to claim 3, characterized in that, In step S1, when the first outer plate is cut into the second outer plate, a bridge is provided between the first outer plate and the second outer plate. When the first inner shell plate is cut into the second inner shell plate, a bridge is provided between the first inner shell plate and the second inner shell plate.

5. The mounting method according to claim 4, characterized in that, The bridges on the outer periphery of the second outer plate and the outer periphery of the second inner shell plate are symmetrically arranged, with a bridge width of 90-120mm. The first outer plate and the first inner shell plate are cut by CNC.

6. The mounting method according to claim 4, characterized in that, Step S3 specifically includes disconnecting the bridge, lifting the process hole section from the side section, turning the process hole section 180° and sending it to the mast for coating on the second outer plate as the base, and turning the side section 180° in the same way and sending it to the mast for coating on the first outer plate as the base.

7. The mounting method according to claim 3, characterized in that, In step S2, the inner shell middle group and the outer shell middle group are first assembled using the first outer shell plate and the first inner shell plate as base surfaces, respectively. Then, using the inner shell middle group as base surface, the outer shell middle group is flipped 180° so that the outer shell middle group and the inner shell middle group are joined and welded together to form a side section with small process hole segments. The outer shell middle group includes a small outer shell middle group, which is a small process hole segment that does not include the second inner shell plate.

8. The mounting method according to claim 7, characterized in that, In step S2, after the inner shell middle group and the outer plate middle group are assembled, before the outer plate middle group is turned over, the longitudinal bones at the adjacent parts of the process hole small segment and the side segment are fixedly connected by the horse plate.

9. The mounting method according to claim 3, characterized in that, Step S2 further includes: after the outer plate middle assembly and the inner shell middle assembly are assembled, a reinforcing member is provided at the joint to connect the second outer plate and the second inner shell plate, and the reinforcing member is removed after S4.

10. The mounting method according to claim 2, characterized in that, The opening size of the first outer plate is larger than the opening size of the first inner shell plate, the process hole segments are wedge-shaped, and the size of the second outer plate is larger than that of the second inner shell plate.

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