Butt-joint installation structure and method for outer pipes of double-wall pipes of dual-fuel ship

Abstract

The invention relates to the technical field of ship equipment, in particular to a double-fuel ship double-wall pipe outer pipe butt joint installation structure which comprises an outer pipe body and an outer pipe connecting pipe, the outer pipe connecting pipe is of a sleeve structure matched with the outer pipe body, a 25-degree chamfer is arranged at the butt joint end of the outer pipe body, the thickness of a reserved root at the root of the chamfer is 0-0.5 mm, and the outer pipe connecting pipe is of a sleeve structure matched with the outer pipe body. The design length of the butt joint position of the outer pipe and the main pipe is 200 mm, and an inner pipe welding and test operation space is reserved; the inner diameter of the outer pipe connecting pipe is larger than the outer diameter of the outer pipe body, and the single-side initial gap between the outer pipe connecting pipe and the outer pipe body before assembly is 0.5 + / -0.1 mm, so that the outer pipe connecting pipe can be quickly sleeved and assembled; the welding single-side gap after the outer pipe connecting pipe and the outer pipe body are assembled is 3 + / -0.5 mm, the outer pipe connecting pipe and the outer pipe body form a staggered angle butt joint structure, and a welding seam is filled by adopting argon tungsten-arc welding and is completely and thoroughly welded. The method has the advantages of being high in construction efficiency and good in machining quality.

Description

Technical Field

[0001] This application relates to the technical field of marine equipment, and in particular to a method for connecting and installing the outer pipe of a double-walled vessel on a dual-fuel ship. Background Technology

[0002] Double-walled pipes are a widely used method for supplying fuel to engines using a dedicated fuel supply system. A double-walled pipe consists of an inner pipe and an outer pipe. The inner pipe carries marine fuel gas, and the annular space between the inner and outer pipes utilizes negative pressure ventilation to achieve airflow within the annular space.

[0003] Currently, the HALF pipe butt welding process is commonly used for the installation of the outer pipes of dual-fuel ships. This process requires the sequential welding of two transverse welds and two circumferential welds at both ends, resulting in a total of four welds. After the transverse welds are welded, the bevels of the transverse and circumferential welds need to be ground, which is a complicated and time-consuming process. At the same time, welding deformation is prone to occur during the transverse weld process, and subsequent correction is difficult and costly.

[0004] While there have been attempts to replace HALF pipes with ordinary sleeves in existing technologies, which can reduce the amount of construction work for two transverse welds, gaps will inevitably remain at the overlap between the ordinary sleeve and the outer pipe, which cannot meet the classification society's specifications for weld sealing and structural strength, making it difficult to promote and apply this solution.

[0005] In response to the aforementioned technologies, there is an urgent need for a double-walled pipe-outer-pipe connection technology that can simplify the construction process, reduce the number of welds, ensure weld penetration, eliminate lap joint gaps, and comply with classification society specifications, so as to achieve lean production goals. Summary of the Invention

[0006] To address the problems in the aforementioned background art, this application provides a structure and method for the docking and installation of the outer pipe of the double-walled tube on a dual-fuel ship.

[0007] The technical solution for the double-walled outer pipe docking installation structure of a dual-fuel ship provided in this application is as follows: A dual-fuel ship double-walled outer tube butt joint installation structure includes an outer tube body and an outer tube connecting tube. The outer tube connecting tube is a sleeve structure adapted to the outer tube body. The butt joint end of the outer tube body is provided with a 25° chamfer, and the root thickness of the chamfer is 0-0.5mm. The designed length of the butt joint of the outer tube body is 200mm to reserve space for inner tube welding and test operations. The inner diameter of the outer tube connecting tube is larger than the outer diameter of the outer tube body. The initial gap on one side before assembly is 0.5±0.1mm to facilitate quick insertion and assembly of the outer tube connecting tube. After assembly, the weld gap on one side of the outer tube connecting tube and the outer tube body is 3±0.5mm, forming a staggered corner butt joint structure. The weld is filled with tungsten inert gas welding and achieves complete penetration.

[0008] The technical solution provided in this application for a method of connecting and installing the outer pipe of a double-walled tube on a dual-fuel ship is as follows: Includes the following steps, Step 1, Pre-treatment: Cut the outer tube to the preset length according to the design requirements, and perform 25° chamfering on the joint ends to ensure that the thickness of the root is controlled at 0-0.5mm. Remove oxide scale, oil stains and other impurities from the surface of the tube ends. Step 2, preparation of outer tube connecting pipe: a special sleeve is customized as the outer tube connecting pipe according to the outer diameter of the outer tube, ensuring that the initial one-sided gap between its inner diameter and the outer diameter of the outer tube is 0.5±0.1mm; Step 3, gap adjustment: Insert the outer pipe connecting pipe into the butt joint ends of the outer pipe on both sides, measure the welding gap on one side, if the gap exceeds the tolerance, process the length of the outer pipe on one side and make secondary corrections to the bevel until the gap meets the requirement of 3±0.5mm. Step 4, Positioning and Assembly: Use temporary supports to fix the relative position of the outer pipe connecting pipe and the outer pipe itself to ensure the stability of the misaligned angle butt joint structure and avoid displacement during welding; Step 5, Welding Operation: Weld the misaligned corner joints using tungsten inert gas welding, with multiple layers of filler welds to ensure complete penetration, free from slag inclusions, porosity, and incomplete fusion defects, and to eliminate lap joint gaps. Quality inspection: After welding is completed, the weld is visually inspected and non-destructive tested to confirm that the weld quality meets the classification society's specifications and design requirements.

[0009] In summary, this application includes at least one of the following beneficial technical effects: 1. This application uses a special sleeve to replace the HALF pipe, reducing the welding and grinding processes of two transverse welds and greatly improving construction efficiency; by precisely controlling the gap size and using staggered corner butt welding and tungsten inert gas welding processes, the weld is fully penetrated, eliminating lap joint gaps and meeting the requirements of classification society specifications; the number of welds and deformation correction work is reduced, the construction period is shortened, and the consumption of welding materials and subsequent maintenance costs are reduced. Attached Figure Description

[0010] Figure 1 This is a schematic diagram of a dual-fuel ship double-walled outer pipe docking installation structure according to an embodiment of this application.

[0011] Figure 2 This is a schematic diagram of the welding of the outer tube and the connecting tube after assembly in the embodiments of this application.

[0012] Explanation of reference numerals in the attached diagram: 1. Outer pipe connecting pipe; 2. Outer pipe itself. Detailed Implementation

[0013] The following is in conjunction with the appendix Figure 1-2 This application will be described in further detail.

[0014] This application discloses a structure for the docking and installation of the outer pipe of a double-walled vessel on a dual-fuel ship. (Refer to...) Figure 1 and Figure 2 The installation structure includes an outer tube 2 and an outer tube connecting tube 1. The outer tube connecting tube 1 has a special sleeve structure, with its inner diameter slightly larger than the outer diameter of the outer tube 2. The butt joint of the outer tube 2 has a 25° chamfer, and the root thickness is 0.3mm. The length of the butt joint of the outer tube 2 is 200mm, and the length of the outer tube connecting tube 1 is 230mm. The initial one-sided gap 5 between the outer tube connecting tube 1 and the outer tube 2 is 0.5mm, and the welded one-sided gap after assembly is 3mm, forming a staggered corner butt joint structure. The weld is filled and fully penetrated using tungsten inert gas welding.

[0015] This application also discloses a method for connecting and installing the outer pipe of a dual-fuel ship with double-walled outer pipe: Step 1, Pre-treatment: Cut the outer tube and the inner tube to the preset length according to the design requirements, and perform 25° chamfering on the joint ends to ensure that the thickness of the root is controlled at 0-0.5mm. Remove oxide scale, oil stains and other impurities from the surface of the tube ends. Step 2, preparation of outer tube connecting pipe 1: a special sleeve is customized as outer tube connecting pipe 1 according to the outer diameter of the outer tube 2, ensuring that the initial one-sided gap between its inner diameter and the outer diameter of the outer tube 2 is 0.5±0.1mm; Step 3, gap adjustment: Insert the outer pipe connecting pipe 1 into the butt joint end of the outer pipe main pipe 2 on both sides, measure the welding gap on one side between the two. If the gap exceeds the tolerance, perform length processing and beveling correction on one side of the outer pipe main pipe 2 until the gap meets the requirement of 3±0.5mm. Step 4, Positioning and Assembly: Use temporary supports to fix the relative positions of the outer pipe connecting pipe 1 and the outer pipe main pipe 2 to ensure the stability of the misaligned angle butt joint structure and avoid displacement during welding. Step 5, Welding Operation: Weld the misaligned corner joints using tungsten inert gas welding, with multiple layers of filler welds to ensure complete penetration, free from slag inclusions, porosity, and incomplete fusion defects, and to eliminate lap joint gaps. Quality inspection: After welding is completed, the weld is visually inspected and non-destructive tested (such as radiographic testing or ultrasonic testing) to confirm that the weld quality meets the classification society's specifications and design requirements.

[0016] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A dual-fuel ship double-walled outer pipe docking and installation structure, characterized in that: The device includes an outer tube and an outer tube connecting tube. The outer tube connecting tube is a sleeve structure adapted to the outer tube. The butt joint of the outer tube has a 25° chamfer, with a root thickness of 0-0.5mm at the chamfer root. The designed length of the butt joint of the outer tube is 200mm to reserve space for welding and testing of the inner tube. The inner diameter of the outer tube connecting tube is larger than the outer diameter of the outer tube. The initial gap on one side before assembly is 0.5±0.1mm to facilitate quick insertion and assembly of the outer tube connecting tube. After assembly, the weld gap on one side of the outer tube connecting tube and the outer tube is 3±0.5mm, forming a staggered corner butt joint structure. The weld is filled with tungsten inert gas welding and achieves complete penetration.

2. A method for connecting and installing the outer pipe of a double-walled tube on a dual-fuel ship based on claim 1, characterized in that: Includes the following steps, Step 1, Pre-treatment: Cut the outer tube to the preset length according to the design requirements, and perform 25° chamfering on the joint ends to ensure that the thickness of the root is controlled at 0-0.5mm. Remove oxide scale, oil stains and other impurities from the surface of the tube ends. Step 2, preparation of outer tube connecting pipe: a special sleeve is customized as the outer tube connecting pipe according to the outer diameter of the outer tube, ensuring that the initial one-sided gap between its inner diameter and the outer diameter of the outer tube is 0.5±0.1mm; Step 3, gap adjustment: Insert the outer pipe connecting pipe into the butt joint ends of the outer pipe on both sides, measure the welding gap on one side, if the gap exceeds the tolerance, process the length of the outer pipe on one side and make secondary corrections to the bevel until the gap meets the requirement of 3±0.5mm. Step 4, Positioning and Assembly: Use temporary supports to fix the relative position of the outer pipe connecting pipe and the outer pipe itself to ensure the stability of the misaligned angle butt joint structure and avoid displacement during welding; Step 5, Welding Operation: Weld the misaligned corner joints using tungsten inert gas welding, with multiple layers of filler welds to ensure complete penetration, free from slag inclusions, porosity, and incomplete fusion defects, and to eliminate lap joint gaps. Quality inspection: After welding is completed, the weld is visually inspected and non-destructive tested to confirm that the weld quality meets the classification society's specifications and design requirements.

Images