Installation process for single-point anchor chain disc of inner turret

Abstract

The invention discloses a process for installing a single-point anchor chain disc of an inner turret, which mainly comprises the following steps of: placing a cushion pier, and sectionally arranging the bottom of a vertical pipe on the cushion pier in place; the chain stopper box section is connected to the vertical pipe bottom section in a spot welding mode; longitudinal rib plates are connected to the chain stopper box sections; frame rib plates are connected between the longitudinal rib plates and the chain stopper box sections; lateral fan-shaped cover plates are connected to the sections of the chain stopper box; a casting supporting frame is connected to the longitudinal rib plates; and the vertical pipe top section is installed, and it is guaranteed that the vertical pipe top section is aligned with the vertical pipe bottom section. According to the installation technology of the inner turret single-point anchor chain plate, the anchor chain plate with the complex internal structural form is divided into multiple sections in advance for synchronous prefabrication, and the installation operation efficiency is improved; the personnel operation safety problem caused by a closed structure is fully considered in the installation sequence, closed space operation is reduced, and the personnel construction safety is remarkably improved.

Description

Technical Field

[0001] This invention belongs to the field of shipbuilding and marine engineering technology, and particularly relates to an installation process for a single-point anchor chain disc for a floating production storage and offloading (FPSO) turret. Background Technology

[0002] Currently, in floating liquefied natural gas production storage and offloading (FPSO) units with internal turret single-point mooring systems, the anchor chain disc is one of its important components. Due to its semi-enclosed structure and highly complex internal configuration, with numerous risers of varying bending angles, the existing anchor chain disc installation method generally adopts the integral reverse-engineering method.

[0003] The reverse construction method for installing anchor chain discs results in a large number of enclosed spaces, which makes it difficult for personnel to enter the site for construction. Construction in enclosed spaces also poses certain safety hazards. The concentricity between different parts is poor. Since the riser is prefabricated as a whole, the internal riser installation accuracy error is large, and the stability during installation is poor. When integrated with the lower tower of the single-point mooring system, problems such as low positioning accuracy and tolerances between the riser and the cylinder may occur.

[0004] Therefore, it is urgent to design an installation process for a single-point anchor chain disc on an internal turret to solve the problems mentioned above. Summary of the Invention

[0005] To address the technical problems mentioned in the background art, such as low positioning accuracy and excessive tolerances between risers and cylinders during the integration of the lower tower body of a single-point mooring system, an installation process for the single-point anchor chain disc of the inner turret is provided to solve the problem of large accuracy errors during the overall installation of the anchor chain disc.

[0006] To achieve the above objectives, the specific technical solution for the installation process of the single-point anchor chain disc of the inner turret of the present invention is as follows: An installation process for a single-point anchor chain disc on an inner turret mainly includes the following steps: S1. Place the support blocks and position the bottom section of the riser on the support blocks; S2. Spot weld the chain stopper box to the bottom section of the riser pipe in sections; S3. Connect longitudinal ribs to the chain stopper box segments; S4. Connect the frame stiffener between the longitudinal rib and the chain stopper box segment; S5. Connect the side fan-shaped cover plate to the chain stopper box segment; S6. Connect the casting support frame to the longitudinal ribs; S7. Install the top section of the riser, ensuring that the top section of the riser is aligned with the bottom section of the riser.

[0007] Furthermore, in S1, the surface of the support block is first leveled, and then the bottom section of the riser is placed on the support block.

[0008] Furthermore, in S3, longitudinal ribs are spot-welded to the chain stopper box segments.

[0009] Furthermore, in S5, the lateral fan-shaped cover plate is spot-welded to the connection between the chain stopper box segment and the longitudinal rib.

[0010] Furthermore, after completing the installation steps S1-S5, the assembly accuracy between the chain stopper box segments, frame stiffeners, and side fan-shaped cover plates is checked. After passing the inspection, the spot welding positions are fully welded.

[0011] Furthermore, in S6, the lower ring plate is first installed on the longitudinal rib plate, then the casting support frame is connected, and finally the upper ring plate is installed.

[0012] Furthermore, after the top section of the riser is installed, the lower half of the conical cover plate is installed.

[0013] Furthermore, a connecting plate is installed between the lower half of the conical cover plate and the chain stopper box segment.

[0014] Furthermore, an annular casting is installed on the top section of the riser, and a conical cover plate is installed on the upper half of the annular casting.

[0015] Further, install guides and bottom support ribs for the oil tank, and then install the anode after overall coating.

[0016] The installation process of the single-point anchor chain disc of the inner turret of the present invention has the following advantages: By pre-disassembling the complex internal structure of the anchor chain disc into multiple segments for simultaneous prefabrication, installation efficiency is improved. The installation sequence fully considers personnel safety issues arising from the enclosed structure, reducing work in confined spaces and significantly improving personnel safety. This application also addresses the problem of large precision errors during overall installation by disassembling risers with different bending angles into multiple segments. Real-time monitoring and control of concentricity during installation improves accuracy when integrating with the single-point tower body, while simultaneously reducing tolerances between risers and between the tower body and the main structure. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of the single-point anchor chain disc of the inner turret of the present invention; Figure 2 This is a schematic diagram of the installation of the bottom section of the riser pipe of the single-point anchor chain disc of the inner turret of the present invention; Figure 3 This is a schematic diagram of the segmented installation of the chain stopper box of the single-point anchor chain disc of the inner turret of the present invention; Figure 4 This is a schematic diagram of the longitudinal rib plate installation of the single-point anchor chain disc of the inner turret of the present invention. Figure 5This is a schematic diagram of the frame stiffener installation for the single-point anchor chain disc of the inner turret of the present invention. Figure 6 This is a schematic diagram of the installation of the side fan-shaped cover plate of the single-point anchor chain disc of the inner turret of the present invention; Figure 7 This is a schematic diagram of the installation of the casting support frame for the single-point anchor chain disc of the inner turret of the present invention; Figure 8 This is a schematic diagram of the top section structure of the riser of the single-point anchor chain disc of the inner turret of the present invention; Figure 9 This is a schematic diagram of the installation of the lower half of the conical cover plate of the single-point anchor chain disc of the inner turret of the present invention. Figure 10 This is a schematic diagram of the installation of the connecting plate of the single-point anchor chain disc of the inner turret of the present invention; Figure 11 This is a schematic diagram of the installation of the annular casting of the single-point anchor chain disc of the inner turret of the present invention; Figure 12 This is a schematic diagram of the upper half of the conical cover plate of the single-point anchor chain disc of the inner turret of the present invention. Figure 13 This is a schematic diagram showing the guide of the single-point anchor chain disc of the inner turret and the installation of the bottom support rib plate of the oil tank in this invention.

[0018] Explanation of markings in the diagram: 1. Bottom section of riser; 2. Chain stopper box section; 3. Top section of riser; 4. Longitudinal rib; 5. Frame stiffener; 6. Lateral fan-shaped cover plate; 7. Casting support frame; 8. Lower half of conical cover plate; 9. Connecting plate; 10. Annular casting; 11. Upper half of conical cover plate; 12. Guide and bottom support stiffener plate of oil sump. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Those skilled in the art will understand that although some embodiments herein include certain features included in other embodiments but not others, combinations of features from different embodiments are intended to be within the scope of the invention and form different embodiments. For example, in the claims, any of the claimed embodiments can be used in any combination.

[0021] The following is a reference to the appendix. Figure 1 To be continued Figure 13The installation process of the single-point anchor chain disc of the inner turret of the present invention is described.

[0022] As a preferred embodiment, such as Figures 2 to 13 As shown, the installation process of the inner turret single-point anchor chain disc in this invention mainly includes the following steps: S1. First, level the surface of the support block and place the prefabricated bottom section 1 of the riser on the support block. S2. Spot weld the chain stopper box into section 2 on section 1 at the bottom of the riser, and spot weld the auxiliary bulk parts. S3. Connect longitudinal ribs 4 to the chain stopper box segment 2. The longitudinal ribs 4 are spot welded to the chain stopper box segment 2. S4. Connect the frame stiffener plate 5 between the longitudinal rib plate 4 and the chain stopper box segment 2; S5. The lateral fan-shaped cover plate 6 is spot-welded to the chain stopper box segment 2, and the lateral fan-shaped cover plate 6 is spot-welded to the spot-welded connection between the chain stopper box segment 2 and the longitudinal rib plate 4. S6. Spot weld the casting support frame 7 on the longitudinal rib plate 4, and check the assembly accuracy between the chain stopper box segment 2, the frame stiffener plate 5 and the side fan-shaped cover plate 6. After the inspection is qualified, the spot welding position is fully welded. In S6, certain welding processes and temporary support rods are used to control welding deformation. This process is existing technology and will not be described in detail here.

[0023] S7. Install the top section 3 of the riser, ensuring that the top section 3 of the riser is aligned with the bottom section 1 of the riser. In S7, after the top section 3 of the riser is in place, all welds are fully welded while ensuring concentricity. The coordinates of the pipe to be inserted are measured and compared with the coordinates of the insertion hole in the top section 3 of the riser, and necessary adjustments are made.

[0024] S8. After the top section 3 of the riser is installed, install the lower half of the conical cover plate 8. S9. Install a connecting plate 9 between the lower half 8 of the conical cover plate and the chain stopper box segment 2; S10. Install an annular casting 10 on the top section 3 of the riser pipe, and set the upper half of the conical cover plate 11 on the annular casting 10. In S10, pay close attention to the concentricity of the casting and the anchor chain disc, as well as the diameter, levelness and out-of-roundness errors of the top of the top cylinder of the casting. After recording the data in detail, check it against the corresponding data at the bottom of the middle tower cylinder. If the matching error will cause foreseeable problems such as misalignment and excessive seam, it should be corrected before the middle tower is painted.

[0025] S11. Install the guide and bottom support rib plate 12 of the oil tank, then apply the overall coating and install the anode. The overall installation is now complete.

[0026] Based on the installation process of the single-point anchor chain disc of the internal turret, this invention pre-disassembles the complex internal structure of the anchor chain disc into multiple segments for simultaneous prefabrication, improving installation efficiency. The installation sequence fully considers the safety issues of personnel operations caused by the enclosed structure, reducing work in confined spaces and significantly improving personnel safety. This application also disassembles risers with different bending angles into multiple segments for installation, solving the problem of large precision errors during overall installation. Real-time monitoring and control of concentricity during installation improves the accuracy when integrating with the single-point lower tower body, while simultaneously reducing tolerances between risers and between the tower body.

[0027] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. An installation process for a single-point anchor chain disc on an inner turret, characterized in that, The main steps include: S1. Place the support blocks and position the bottom section of the riser on the support blocks; S2. Spot weld the chain stopper box to the bottom section of the riser pipe in sections; S3. Connect longitudinal ribs to the chain stopper box segments; S4. Connect the frame stiffener between the longitudinal rib and the chain stopper box segment; S5. Connect the side fan-shaped cover plate to the chain stopper box segment; S6. Connect the casting support frame to the longitudinal ribs; S7. Install the top section of the riser, ensuring that the top section of the riser is aligned with the bottom section of the riser.

2. The installation process of the single-point anchor chain disc of the inner turret according to claim 1, characterized in that, In S1, the surface of the support block is first leveled, and then the bottom section of the riser is placed on the support block.

3. The installation process of the single-point anchor chain disc of the inner turret according to claim 1, characterized in that, In S3, longitudinal ribs are spot-welded to the chain stopper box segments.

4. The installation process of the single-point anchor chain disc of the inner turret according to claim 1, characterized in that, In S5, the lateral fan-shaped cover plate is spot-welded to the connection between the chain stopper box segment and the longitudinal rib plate.

5. The installation process of the single-point anchor chain disc of the inner turret according to claim 1, characterized in that, After completing the installation steps S1-S5, the assembly accuracy between the chain stopper box segments, frame stiffeners and side fan-shaped cover plates is checked. After passing the inspection, the spot welding positions are fully welded.

6. The installation process of the single-point anchor chain disc of the inner turret according to claim 1, characterized in that, In S6, the lower ring plate is first installed on the longitudinal rib plate, then the casting support frame is connected, and finally the upper ring plate is installed.

7. The installation process of the single-point anchor chain disc of the inner turret according to claim 1, characterized in that, After the top section of the riser is installed, install the lower half of the conical cover plate.

8. The installation process of the single-point anchor chain disc of the inner turret according to claim 7, characterized in that, A connecting plate is installed between the lower half of the conical cover plate and the chain stopper box segment.

9. The installation process of the single-point anchor chain disc of the inner turret according to claim 1, characterized in that, An annular casting is installed on the top section of the riser, and a conical cover plate is installed on the upper half of the annular casting.

10. The installation process of the single-point anchor chain disc of the inner turret according to claim 9, characterized in that, Install guides and bottom support ribs for the oil tank, then apply the coating as a whole and install the anode.

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