Method for manufacturing a double-walled tank shell

Abstract

The application discloses a manufacturing method of a double-ear type storage tank cylinder, and belongs to the technical field of the manufacturing method of the double-ear type storage tank cylinder. The manufacturing method comprises the following steps: manufacturing cylinder segment blocks, assembling and welding a single-side cylinder to cut off the embedded cylinder segment to form a first side cylinder and a second side cylinder in a C type, and installing a longitudinal partition plate to fold the first side cylinder and the second side cylinder. The manufacturing method has the following technical advantages: 1. The embedded cylinder segment blocks can be reused to solve the problems of roundness maintenance and assembly precision of the first side cylinder and the second side cylinder in the assembly and welding process; 2. The embedded cylinder segment blocks and the body cylinder segment blocks are assembled and welded to form a plurality of circular cylinder segments, and the assembly and welding of the circular cylinder segment ring seams are carried out on a welding roller frame, so that the problems that the first side cylinder and the second side cylinder cannot be automatically or semi-automatically welded due to the incomplete structure are solved; and 3. The assembly platform is used to avoid the problem that a large number of scaffolds need to be erected for high-altitude operation in the assembly and welding process of the first side cylinder, the second side cylinder and the longitudinal partition plate.

Description

Technical Field

[0001] This invention relates to the field of LNG carrier technology, and specifically to a method for manufacturing a double-eared storage tank body. Background Technology

[0002] LNG (liquefied natural gas) carriers are a crucial part of the LNG industry chain, acting as "super-refrigerated trucks" for transporting LNG at sea. They have become the main mode of ocean-going natural gas transportation, while LNG storage tanks are the core equipment of Type C independent-cabin LNG carriers. With the surge in domestic LNG demand and transportation volume, LNG carriers and LNG storage tanks are also developing towards larger sizes.

[0003] Currently, to increase loading capacity, large LNG carriers generally use double-eared tank structures for their LNG storage tanks. This design offers advantages such as reduced equipment, optimized internal layout, and large cargo capacity. The double-eared tank consists of two sets of C-shaped sections connected by longitudinal bulkheads, forming a structure of two intersecting single cylinders. Unlike typical cylindrical tanks, the two sets of C-shaped sections in a double-eared tank are not complete cylindrical structures. Whether welding the sections vertically or horizontally, the circumferential seam can only be welded using shielded metal arc welding (SMAW) in all positions or horizontally. This results in low welding efficiency, high welding difficulty, difficulty in ensuring welding quality, and poor weld surface finish. The process is complex, construction is challenging, and extensive surface grinding of the welds is required.

[0004] Therefore, designing a novel method for assembling and welding the cylinder of a double-eared storage tank for LNG carriers is a pressing technical challenge that needs to be addressed in the installation of large double-eared storage tanks. Summary of the Invention

[0005] In order to overcome the technical problems described in the prior art, the present invention aims to provide a method for manufacturing a double-eared storage tank body.

[0006] This invention provides a method for manufacturing a double-eared storage tank body, comprising the following steps:

[0007] Step 1: Fabricate cylindrical sections: The double-eared storage tank body includes a first side cylinder, a second side cylinder, and longitudinal partition plates. Several main cylindrical sections and insert cylindrical sections are fabricated to assemble the first side cylinder and the second side cylinder.

[0008] Step 2: Assemble and weld the first side cylinder: On the assembly platform, vertically weld several main cylinder sections and patch cylinder sections to form several circular cylinder sections. Rotate each circular cylinder section 90 degrees and hoist it onto the welding roller frame to horizontally weld it to form a single-side cylinder. Hoist the single-side cylinder onto the assembly platform and place it vertically. Cut and remove the patch cylinder sections to form a C-shaped first side cylinder.

[0009] Step 3: Assemble and weld the second side cylinder: Repeat step 2 to complete the assembly and welding of the second side cylinder, which has an axisymmetric structure with the first side cylinder;

[0010] Step 4: Join the first and second side cylinders: Insert longitudinal partition plates between the first and second side cylinders on the assembly platform and weld them together to form a double-eared storage tank cylinder.

[0011] As a preferred technical solution, step 1 also includes the following: based on the circumference and height of the double-eared storage tank, the number of main body sections, insert sections, and circular sections are determined.

[0012] As a preferred technical solution, when making the patching cylinder section in step 1, ordinary steel plates are used for the patching cylinder section to reduce material costs.

[0013] As a preferred technical solution, when making the body cylinder section in step 1, the body cylinder section that is welded to the insert cylinder section should retain a cutting allowance of 30-40mm.

[0014] As a preferred technical solution, before assembling and welding the first side cylinder in step 2, an assembly platform needs to be set up. The assembly platform setup includes the following: first, prepare several assembly jigs that can be fixed to the ground, draw the layout line of the assembly jigs along the vertical projection of the first side cylinder, and then evenly distribute the several assembly jigs along the layout line and fix them to the ground to complete the setup, so that several main body cylinder sections and insert cylinder sections can be vertically assembled.

[0015] As a preferred technical solution, a welding roller frame needs to be erected before assembling and welding the first side cylinder in step 2. The erection of the welding roller frame includes the following: first, prepare three sets of support rods that can be fixed to the ground, distribute the three sets of support rods evenly at intervals according to the radial dimensions of the circular cylinder section and fix them to the ground, and symmetrically arrange two sets of pulleys on the top of the support rods to complete the erection, so that the circular cylinder section can be rotatably placed on the welding roller frame for circumferential welding of adjacent circular cylinder sections.

[0016] As a preferred technical solution, in step 2, the single-sided cylinder is hoisted to the assembly platform and the patched cylinder section is cut and removed to form the first side cylinder. The removed patched cylinder section is then used for the assembly and welding of the second side cylinder.

[0017] As a preferred technical solution, the main body section segmentation and the insert section segmentation in step S1 are formed by roller forming.

[0018] As a preferred technical solution, in steps 2 and 3, when each cylindrical section is rotated 90 degrees and hoisted onto the welding roller frame for assembly welding, a temporary inner support frame is added inside each cylindrical section to prevent the cylindrical section from deforming due to its own weight.

[0019] As a preferred technical solution, after step S4, the following steps are also included: performing non-destructive testing on the double-eared storage tank body; wherein the testing methods include radiographic testing, ultrasonic testing, dye penetrant testing, and visual inspection.

[0020] In summary, the present invention has the following technical effects:

[0021] The present invention discloses a method for manufacturing a double-eared storage tank body. This method includes manufacturing segmented cylinders, assembling and welding a first side cylinder, assembling and welding a second side cylinder, closing the first and second side cylinders, and welding the C-shaped cylinders on both sides of the double-eared storage tank to the longitudinal partition plate. In the assembly and welding of the first and second side cylinders, the main body cylinder segmented cylinders and the patched cylinder segmented cylinders are used, and the patched cylinder segmented cylinders are subsequently cut and removed. The above-mentioned method for manufacturing a double-eared storage tank has the following technical advantages: 1. This application uses a method of assembling the main body cylinder into a circular cylinder structure by using reusable interlocking cylinder sections, which solves the problem of maintaining roundness and assembly accuracy during the welding process of the C-shaped first and second side cylinders; 2. This application uses interlocking cylinder sections and main body cylinder sections to first assemble and weld several circular cylinder sections for forming the first and second side cylinders, and then assembles and welds the circumferential seams of each circular cylinder section on a welding roller frame, which solves the problem of maintaining roundness and assembly accuracy during the welding process of the C-shaped first and second side cylinders; The present invention addresses the challenge of achieving automatic or semi-automatic welding of the side cylinders due to their incomplete structure. It improves the quality and efficiency of circumferential welding in double-eared storage tanks, eliminating the need for surface grinding of the weld seams. Furthermore, this application employs a novel method for welding the first and second side cylinders and longitudinal partition plates on an assembly platform. This avoids the need for extensive scaffolding and high-altitude work during the assembly of the first and second side cylinders, reducing the difficulty of assembly and improving the construction quality of the double-eared storage tank. Therefore, compared to existing double-eared storage tank manufacturing technologies, the manufacturing method for a double-eared storage tank provided by this invention has significant technical advantages. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0023] Figure 1 This is a three-dimensional structural diagram of the double-eared storage tank body according to an embodiment of the present invention;

[0024] Figure 2 This is a schematic diagram of the assembly and welding process of the first side cylinder according to an embodiment of the present invention;

[0025] Figure 3 This is a schematic diagram of the process of closing the first side cylinder and the second side cylinder according to an embodiment of the present invention;

[0026] The meanings of the reference numerals in the attached figures are as follows:

[0027] 1-First side cylinder, 11-Main cylinder section, 12-Insertion cylinder section, 2-Second side cylinder, 3-Longitudinal bulkhead, 4-Assembly jig, 5-Welding roller frame, 6-Temporary internal support frame. Detailed Implementation

[0028] The technical solution of this embodiment will be clearly and completely described below with reference to the accompanying drawings. The embodiments described herein are for illustrative purposes only and are not intended to limit the scope of protection of the present invention. Therefore, it should be understood that various modifications and changes can be made to this embodiment without departing from the scope of protection of the present invention.

[0029] In the description of this invention, unless otherwise expressly specified and limited, the term "and / or" includes any and all combinations of one or more of the associated listed items. Unless otherwise specified or stated, the terms "connection," "fixed," etc., should be interpreted broadly; for example, "connection" can be a fixed connection, a detachable connection, an integral connection, an electrical connection, or a signal connection; "connection" can be a direct connection or an indirect connection via an intermediate medium. Those skilled in the art will understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0030] Furthermore, in the description of this invention, it should be understood that the directional terms described in this embodiment are used to describe the angles shown in the accompanying drawings and should not be construed as limiting this embodiment. It should also be understood that, in the context of this invention, when an element or feature is mentioned as being connected to another element (one or more), it can be directly connected to the other element (one or more) or indirectly connected to the other element (one or more) through an intermediate element.

[0031] Before introducing the technical solution of this invention, it is necessary to explain the background of its creation. Currently, to increase loading capacity, large LNG carriers commonly use double-eared tank structures for their LNG storage tanks. This design offers advantages such as reduced equipment, optimized internal layout, and large cargo capacity. The double-eared tank's cylinder is formed by connecting two sets of C-shaped sections with longitudinal bulkheads, resulting in a structure of two intersecting single cylinders. Unlike typical cylindrical tanks, the two sets of C-shaped sections in the double-eared tank are not complete cylindrical structures. Whether welding the sections vertically or horizontally, the circumferential seam can only be welded in all positions or horizontally using shielded metal arc welding. This results in low welding efficiency, high welding difficulty, difficulty in ensuring welding quality, and poor weld surface finish. The process is complex, construction is difficult, and extensive surface grinding of the weld is required.

[0032] To overcome the technical problems of the prior art, the present invention aims to provide a method for manufacturing a double-eared storage tank body. Please refer to... Figures 1 to 3 An exemplary embodiment of the present invention provides a method for manufacturing a double-eared storage tank body. A reusable patched cylindrical section 12 is used to assemble the main cylindrical section 11 of the double-eared storage tank body into a circular cylindrical section structure. The circular cylindrical section circumferential seam is assembled and welded on a welding roller frame 5 using submerged arc welding to form a circular cylinder. The circular cylindrical section is then rotated 90 degrees and placed vertically on an assembly platform. The patched cylindrical section 12 is cut off to form a C-shaped first side cylinder 1. The cut-off patched cylindrical section 12 can be used in the welding of a second side cylinder 2 that is symmetrical to the first side cylinder 1. After forming the circular cylinder, the patched cylindrical section 12 is similarly cut off to form the second side cylinder 2. Finally, the C-shaped first side cylinder 1 and second side cylinder 2 are welded to the intermediate longitudinal partition plate 3, completing the manufacturing of the double-eared storage tank body. This manufacturing method features an ingenious assembly method for the cylinder sections, resulting in high assembly efficiency. It allows for automated submerged arc welding, ensuring high-quality and reliable welding, and producing excellent weld surface finish, eliminating the need for weld surface grinding. Please refer to [link / reference]. Figures 1 to 3 This method of production includes the following steps:

[0033] Step 1: Fabrication of cylindrical sections: The double-eared storage tank includes a first side cylinder 1, a second side cylinder 2, and a longitudinal partition plate 3. Several main cylindrical sections 11 and insert cylindrical sections 12 are fabricated to form the first side cylinder 1 and the second side cylinder 2.

[0034] It should be noted that, in some embodiments, step 1 further includes the following: Based on the circumference and height of the double-eared storage tank body, the number of main body cylindrical sections 11, patch cylindrical sections 12, and circular cylindrical sections is determined. Preferably, in this embodiment, three sets of circular cylindrical sections are used. In some embodiments, when fabricating the patch cylindrical sections 12 in step 1, the main body cylindrical section 11 is made of 7Ni steel, which has high strength and excellent low-temperature toughness. The patch cylindrical section 12 is made of ordinary steel plate, as the patch cylindrical section 12 will detach from the double-eared storage tank body during subsequent cutting; using ordinary steel plate reduces material costs. In some embodiments, when fabricating the main body cylindrical section 11 in step 1, the main body cylindrical section 11 that is welded to the patch cylindrical section 12 should retain a cutting allowance of 30-40mm to avoid damaging the structure of the first side cylinder 1 or the second side cylinder 2 during subsequent cutting. As a preferred technical solution, in some embodiments, the main body section block 11 and the insert section block 12 in step S1 are formed by roller forming.

[0035] Step 2: Assemble and weld the first side cylinder 1: On the assembly platform, vertically weld several main body cylinder sections 11 and insert cylinder sections 12 to form three sets of circular cylinder sections. Rotate each circular cylinder section 90 degrees and hoist it onto the welding roller frame 5 to horizontally weld it to form a single-sided cylinder. Hoist the single-sided cylinder onto the assembly platform and place it vertically. Cut and remove the insert cylinder section 12 to form a C-shaped first side cylinder 1.

[0036] It should be noted that before assembling and welding the first side cylinder in step 2, an assembly platform needs to be erected. The erection of the assembly platform includes the following: first, preparing several assembly jigs that can be fixed to the ground, such as... Figure 2 As shown, this assembly jig can clamp the main body cylindrical section and the insert cylindrical section. The assembly jig layout line is drawn along the vertical projection of the first side cylinder. Several assembly jigs are then evenly distributed along the layout line and fixed on the ground to complete the erection, so that several main body cylindrical section and insert cylindrical section can be vertically assembled and arranged.

[0037] Furthermore, in some embodiments, before assembling and welding the first side cylinder 1 in step 2, a welding roller frame 5 needs to be erected. The erection of the welding roller frame 5 includes the following: first, prepare three sets of support rods that can be fixed to the ground; distribute the three sets of support rods evenly at intervals according to the radial dimensions of the circular cylinder section and fix them to the ground; symmetrically arrange two sets of pulleys on the top of the support rods to complete the erection, so that the circular cylinder section can be rotatably placed on the welding roller frame for circumferential welding of adjacent circular cylinder sections. After the circumferential welding of two adjacent circular cylinder sections is completed, a third set of welding roller frames is set on both sides for subsequent circumferential welding of cylinder sections.

[0038] Step 3: Assemble and weld the second side cylinder 2: Repeat step 2 to complete the assembly and welding of the second side cylinder 2, which is axially symmetrical to the first side cylinder 1. It should be noted that, as a preferred technical solution, in some embodiments, in step 2, the single-side cylinder is hoisted to the assembly platform and the patch cylinder section 12 is cut and removed to form the first side cylinder 1. The removed patch cylinder section 12 is then used for the assembly and welding of the second side cylinder. The method of assembling the main body cylinder section 11 into a circular cylinder structure using reusable patch cylinder section 12 solves the problem of maintaining the roundness and assembly accuracy of the C-shaped first side cylinder 1 and second side cylinder 2 during the assembly and welding process.

[0039] In addition, as a preferred technical solution, please refer to Figure 2 In some embodiments, when each cylindrical section is rotated 90 degrees and hoisted onto the welding roller frame 5 for welding in steps 2 and 3, a temporary inner support frame 6 is added inside each cylindrical section. The temporary inner support frame 6 consists of several crossbars inserted into the cylindrical section and abutting against its inner wall to prevent the cylindrical section from deforming due to its own weight.

[0040] Step 4: Joining the First Side Tank 1 and the Second Side Tank 2: Place the first side tank 1 and the second side tank 2 on the assembly platform, and then place the longitudinal partition plate 3 between the first side tank 1 and the second side tank 2 and weld them together to form a double-eared storage tank. Specifically, first, adjust the position of the assembly platform according to the vertical projection of the double-eared storage tank. Place the open sides of the first side tank 1 and the second side tank 2 opposite each other on the assembly platform. Then, hoist the longitudinal partition plate 3 to the junction of the first side tank 1 and the second side tank 2, adjust the weld position of the longitudinal partition plate 3 with the first side tank 1 and the second side tank 2, and connect them with clamps. After the gap, misalignment, angular deformation, straightness, and ellipticity are adjusted to meet the requirements, tack fixation is performed. After tack fixation is completed and inspected and qualified, welding is then performed to complete the joining operation of the first side tank 1 and the second side tank 2.

[0041] It should be noted that after step S4, the following steps are also included: performing non-destructive testing on the double-eared storage tank body; wherein, the testing methods include radiographic testing, ultrasonic testing, dye penetrant testing, and visual inspection.

[0042] In summary, the above-described method for manufacturing a double-eared storage tank has the following technical advantages:

[0043] 1. This application employs a method of assembling reusable insert cylindrical sections into a circular cylindrical structure, solving the problem of maintaining roundness and assembly accuracy during the welding process of the C-shaped first and second side cylinders; 2. This application employs a method of first assembling and welding insert cylindrical sections and main cylinder sections to form several circular cylinders for forming the first and second side cylinders, and then assembling and welding the circumferential seams of each circular cylinder on a welding roller frame, solving the problem that the C-shaped first and second side cylinders cannot be fully assembled due to structural incompleteness. The present application addresses the challenges of automatic or semi-automatic welding, improves the quality and efficiency of circumferential welding of the double-eared storage tank body, and eliminates the need for surface grinding of the weld seam; 3. In this application, a novel method is adopted for welding the first and second side cylinders and longitudinal partition plates on an assembly platform when assembling the first and second side cylinders. This avoids the problem of needing to erect a large amount of scaffolding for high-altitude operations during the assembly of the first and second side cylinders, reduces the difficulty of assembling the first and second side cylinders, and improves the construction quality of the double-eared storage tank body.

[0044] Therefore, compared with existing double-eared storage tank manufacturing technology, the manufacturing method of the double-eared storage tank body provided by this invention has obvious technical advantages.

[0045] 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 the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for manufacturing a double-eared storage tank body, characterized in that, Includes the following steps: Step 1: Fabricate cylindrical sections: The double-eared storage tank body includes a first side cylinder, a second side cylinder, and longitudinal partition plates. Several main cylindrical sections and insert cylindrical sections are fabricated to assemble the first side cylinder and the second side cylinder. Step 2: Assemble and weld the first side cylinder: On the assembly platform, vertically weld several main cylinder sections and patch cylinder sections to form several circular cylinder sections. Rotate each circular cylinder section 90 degrees and hoist it onto the welding roller frame to horizontally weld it to form a single-side cylinder. Hoist the single-side cylinder onto the assembly platform and place it vertically. Cut and remove the patch cylinder sections to form a C-shaped first side cylinder. Step 3: Assemble and weld the second side cylinder: Repeat step 2 to complete the assembly and welding of the second side cylinder, which has an axisymmetric structure with the first side cylinder; Step 4: Join the first and second side cylinders: Insert longitudinal partition plates between the first and second side cylinders on the assembly platform and weld them together to form a double-eared storage tank cylinder.

2. The method for manufacturing the double-eared storage tank body according to claim 1, characterized in that, Step 1 also includes the following: Based on the circumference and height of the double-eared storage tank, determine the number of main body sections, insert sections, and circular sections.

3. The method for manufacturing the double-eared storage tank body according to claim 2, characterized in that, In step 1, when making the patching cylinder section, ordinary steel plates are used for the patching cylinder section to reduce material costs.

4. The method for manufacturing the double-eared storage tank body according to claim 3, characterized in that, When making the body section blocks in step 1, the body section blocks that are welded to the insert section blocks should retain a cutting allowance of 30-40mm.

5. The method for manufacturing the double-eared storage tank body according to claim 1, characterized in that, Before assembling and welding the first side cylinder in step 2, an assembly platform needs to be set up. The assembly platform setup includes the following: first, prepare several assembly jigs that can be fixed to the ground; draw the layout line of the assembly jigs along the vertical projection of the first side cylinder; then distribute the several assembly jigs evenly along the layout line and fix them to the ground to complete the setup, so that several main body cylinder sections and insert cylinder sections can be vertically assembled.

6. The method for manufacturing the double-eared storage tank body according to claim 5, characterized in that, Before assembling and welding the first side cylinder in step 2, a welding roller frame needs to be set up. The setup of the welding roller frame includes the following: First, prepare three sets of support rods that can be fixed to the ground. Distribute the three sets of support rods evenly at intervals according to the radial dimensions of the circular cylinder section and fix them to the ground. Then, symmetrically arrange two sets of pulleys on the top of the support rods to complete the setup, so that the circular cylinder section can be rotatably placed on the welding roller frame for circumferential welding of adjacent circular cylinder sections.

7. The method for manufacturing the double-eared storage tank body according to claim 1, characterized in that, In step 2, the single-sided cylinder is hoisted onto the assembly platform and the patched cylinder section is cut and removed to form the first side cylinder. The removed patched cylinder section is then used for the assembly and welding of the second side cylinder.

8. The method for manufacturing the double-eared storage tank body according to claim 1, characterized in that, In step S1, the main body section segment and the insert section segment are formed by roller forming.

9. The method for manufacturing the double-eared storage tank body according to claim 1, characterized in that, In steps 2 and 3, when each cylindrical section is rotated 90 degrees and hoisted onto the welding roller frame for assembly welding, a temporary internal support frame is added inside each cylindrical section to prevent deformation due to its own weight.

10. The method for manufacturing the double-eared storage tank body according to claim 1, characterized in that, Step S4 is followed by the following: non-destructive testing of the double-eared storage tank body; wherein the testing methods include radiographic testing, ultrasonic testing, dye penetrant testing, and visual inspection.

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