Pipe head welding structure of chlorine liquefier

Abstract

The utility model discloses a chlorine liquefier tube head welding structure which comprises a tube plate and a plurality of heat exchange tubes, and the heat exchange tubes are arranged on the tube plate in a penetrating mode. The length of the part, extending out of the tube plate, of the tube head of the heat exchange tube is 0-1mm; the tube plate is provided with a groove used for being connected with a heat exchange tube, and the angle of the groove ranges from 45 degrees to 60 degrees. The heat exchange tube is in interference fit with the hole wall of the tube plate through expanded connection, and the groove is filled with a welding seam to fixedly connect the heat exchange tube with the tube plate. According to the chlorine liquefier pipe head welding structure, the welding quality of the chlorine liquefier pipe head can be improved, the connection reliability is enhanced, and leakage is effectively prevented.

Description

Technical Field

[0001] This utility model relates to the technical field of chlorine liquefaction device manufacturing, specifically to a chlorine liquefaction device pipe head welding structure. Background Technology

[0002] Chlorine liquefaction units have important applications in chemical, environmental protection, and other fields. Their main function is to convert gaseous chlorine into a liquid state for easy storage and transportation. During the manufacturing process of chlorine liquefaction units, the quality of the connection between the heat exchange tubes and the tube sheet directly affects the performance and service life of the equipment.

[0003] Traditional chlorine liquefaction unit tube welding processes suffer from numerous problems. For instance, improper tube cutting methods, such as using abrasive wheels and relying on manual fixation at the far end, leave the cut end unsecured, allowing the tube to easily rotate. This results in uneven tube ends, and some tube ends extending beyond the tube sheet to the required length. Furthermore, while anti-deformation fixtures are used during tube sheet welding, deformation is still difficult to completely prevent, causing localized tube depressions below the tube sheet plane. These issues lead to insufficient fusion between the welding material and the base material, resulting in thin welds at the tube ends and insufficient weld strength, making leaks more likely during equipment operation. Additionally, long-term use of the tube expander generates built-up edges, damaging the tube ends and creating further quality risks in the tube end welding. Utility Model Content

[0004] The purpose of this invention is to overcome the shortcomings of the above-mentioned background technology and provide a welding structure for the chlorine liquefier pipe head, which can improve the welding quality of the chlorine liquefier pipe head, enhance the connection reliability, and effectively prevent leakage.

[0005] To achieve the above objectives, the present invention provides a chlorine liquefaction device tube head welding structure, comprising a tube sheet and several heat exchange tubes, wherein the heat exchange tubes are inserted through the tube sheet; the length L of the tube head extending out of the tube sheet is 0-1 mm.

[0006] The tube sheet is provided with a bevel for connecting to the heat exchange tube, and the angle of the bevel is 45° to 60°.

[0007] The heat exchange tube and the tube sheet are connected by an expansion joint to form an interference fit, and the groove is filled with a weld to fix the heat exchange tube and the tube sheet.

[0008] Furthermore, the depth of the bevel is 1–2 mm.

[0009] Furthermore, the length of the heat exchange tube extending beyond the tube sheet is 0.2 to 0.8 mm.

[0010] Furthermore, the bevel is a V-shaped bevel.

[0011] Furthermore, the interference between the heat exchange tube and the hole wall of the tube sheet is 0.05 to 0.15 mm.

[0012] Furthermore, the weld is a multi-layer, multi-pass fillet weld.

[0013] Furthermore, the angle of the bevel is 45° to 50°.

[0014] Furthermore, the end face of the heat exchange tube is a smooth and flat tube opening.

[0015] Furthermore, the center distance between two adjacent heat exchange tubes is not less than 1.25 times the outer diameter of the heat exchange tube.

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] Firstly, the welding structure of the chlorine liquefier tube head of this utility model significantly improves the welding quality, effectively solving the problem of tube head leakage caused by issues such as the tube head being lower than the tube sheet plane, insufficient fusion between the welding material and the base material, and insufficient weld strength. This enhances the sealing performance of the chlorine liquefier and improves the overall reliability and stability of the equipment.

[0018] Secondly, the welding structure of the chlorine liquefaction tube head of this utility model reduces the frequency of equipment maintenance and replacement due to welding quality problems, extends the service life of the chlorine liquefaction unit, and reduces equipment maintenance costs.

[0019] Thirdly, the welding structure of the chlorine liquefaction tube head of this utility model improves production efficiency, reduces equipment downtime and production interruptions caused by leakage problems, ensures production continuity, and has good economic and social benefits.

[0020] Fourth, the heat exchange tube head of this invention extends 0-1mm, ensuring complete fusion of the weld on the outside while avoiding stress concentration due to excessive tube length or burn-through due to excessively short tube length, thus significantly reducing leakage. The bevel angle is 45°-60°, forming a natural V-shaped molten pool; the fluidity of the welding material and the wettability of the base material are optimal, reducing slag inclusions and incomplete fusion defects.

[0021] Fifth, the heat exchange tube and the tube sheet hole wall of this utility model form an interference fit through expansion joint, and the groove is filled with weld to fix the heat exchange tube and the tube sheet, realizing the dual sealing and reinforcement of "strength welding + expansion".

[0022] Sixth, the end face of the heat exchange tube of this utility model is a smooth and flat tube opening. The tube opening can be reamed using a flat-end machine after the heat exchange tube is assembled. This method ensures that the tube opening is flat and maintains good parallelism with the tube sheet, effectively avoiding the problem of uneven or dented tube openings caused by improper cutting methods. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the cross-sectional structure of the connection between the heat exchange tubes and the tube sheet;

[0024] Figure 2 A schematic diagram showing the extension length of the heat exchange tube;

[0025] Figure 3 This is a schematic diagram of the bore diameter arrangement in the tube sheet plane.

[0026] Figure 4 for Figure 3 Side sectional view of the tube sheet shown;

[0027] Figure 5 for Figure 3 Enlarged structural diagram at point A;

[0028] In the diagram: 1-Tube sheet, 2-Heat exchange tube, 3-Bevel, 4-Weld. Detailed Implementation

[0029] The following examples illustrate the implementation of this utility model in detail, but they do not constitute a limitation on this utility model and are merely illustrative. Furthermore, explaining the advantages of this utility model will make it clearer and easier to understand.

[0030] like Figures 1-5 The diagram illustrates a chlorine liquefaction unit tube head welding structure, comprising a tube sheet 1 and several heat exchange tubes 2, with the tube heads extending 0-1 mm beyond the tube sheet 1. The tube sheet 1 has a bevel 3 for connecting to the heat exchange tubes 2, with an angle of 45°-60° and a depth of 1-2 mm. This design ensures sufficient strength and sealing between the tube head and the tube sheet during welding and operation. The heat exchange tubes 2 and the tube sheet 1 are connected via an expansion joint to form an interference fit. A weld 4 fills the bevel 3 to securely connect the heat exchange tubes 2 and the tube sheet 1. The tube head end face of the heat exchange tubes 2 is smooth and flat, allowing for tube end reaming using a flat-end mill after assembly. This ensures a flat tube end and good parallelism with the tube sheet, effectively avoiding unevenness or dents caused by improper cutting methods.

[0031] In a preferred embodiment, the length of the heat exchange tube 2 extending beyond the tube sheet 1 is 0.2–0.8 mm. The interference between the heat exchange tube 2 and the hole wall of the tube sheet 1 is 0.05–0.15 mm. The weld 4 is a multi-layer, multi-pass fillet weld. The bevel 3 is a V-shaped bevel with an angle of 45°–50°. The center distance between two adjacent heat exchange tubes 2 is not less than 1.25 times the outer diameter of the heat exchange tube 2.

[0032] The welding process of the chlorine liquefaction tube head welding structure of this utility model is as follows: Several heat exchange tubes 2 are inserted into the through holes of the tube sheet 1. After assembly, the tube ends extending outward from the tube sheet are reamed using a flat-end mill, so that the end face of the heat exchange tube 2 protrudes 0-1mm from the outer surface of the tube sheet 1, and the end face is parallel to the outer plane of the tube sheet. Subsequently, a V-shaped bevel 3 is machined at the corresponding position on the outer side of the tube sheet 1, with a bevel angle of 45°-60° and a depth of 12mm. A multi-layer, multi-pass fillet weld is used to form a weld 4 in the bevel 3, so that the welding material and the base material are fully fused. After welding, a special tube expander is used to expand the heat exchange tube 2 from the inside, so that the outer wall of the heat exchange tube and the tube sheet hole wall form an interference fit of 0.05-0.15mm, achieving a double seal and reinforcement of "strength welding + expansion". The manufactured welded structure is subjected to a 1.5MPa shell-side and tube-side pressure test. No leakage indicates that it is qualified.

[0033] The procedure for manufacturing a new chlorine liquefaction unit is as follows:

[0034] A comprehensive overhaul of the ultrasonic cleaning machine was conducted to ensure the jet tank operated normally. Cleaning personnel received professional training to ensure they were proficient in the standard cleaning process (jetting, ultrasonic cleaning, bubbling, rust prevention, and drying). During the cleaning process, the pH value of the cleaning agent in the tank was regularly checked using pH test strips or professional testing equipment, and the cleaning agent was replaced every 15 days to ensure cleaning effectiveness.

[0035] Inspect all expanders, replace expanders with built-up lumps, and after the expansion operation, use a specialized inspection tool (such as an endoscope) to inspect the tube wall to ensure that the tube wall is undamaged.

[0036] Before welding, use precise measuring tools to measure the length of the heat exchange tube extending out of the tube sheet, ensuring it is within the range of 0-1mm. At the same time, use special cleaning agents and tools to clean the dirt within a 10mm radius around the welding area until the surface is clean and free of impurities.

[0037] During the welding process, the operators strictly follow the parameters set in the welding process card (such as welding current, voltage, welding speed, etc.) to perform the welding. After each weld is completed, the inspector checks it against the requirements of the process card, including whether the weld appearance is smooth, free of porosity and cracks, and whether the welding dimensions meet the design requirements, to ensure that the welding quality meets the standards.

[0038] For chlorine liquefaction units that are already in use and have experienced leaks at the pipe joint welds, the operating procedure is as follows:

[0039] First, conduct a comprehensive inspection of the equipment to determine the location and number of leaking pipe heads.

[0040] Remove the leaking heat exchange tube, replace it with one of sufficient length, and then re-ream it using a flat-end machine so that it extends 0-1mm beyond the tube sheet. Perform a deep cleaning of the tube sheet surface to remove oil and impurities. A combination of chemical cleaning and physical wiping can be used to ensure that the cleanliness of the tube sheet surface meets the welding requirements.

[0041] Replace the tube expander and re-expand the heat exchange tubes. During the expansion process, strictly control the expansion pressure and depth to avoid over-expansion or under-expansion. After expansion, inspect the tube walls again for damage. If any damage is found, repair or replace the heat exchange tubes promptly.

[0042] According to the welding process requirements, the pipe head weld is repaired or re-welded. Before repair welding, the weld is ground to remove defects and ensure a smooth weld surface. During welding, welding parameters are strictly controlled, and a multi-layer, multi-pass welding method is used to ensure full weld filling. After welding, non-destructive testing (such as flaw detection) is performed to ensure that the welding quality is defect-free and that the equipment operates without leaks.

[0043] The welding structure of this invention effectively solves the problem of pipe weld leakage, improving equipment performance and reliability, whether for newly manufactured chlorine liquefiers or for retrofitting existing equipment. In practical applications, the appropriate implementation method can be selected based on the specific equipment and production needs.

[0044] The above are merely specific embodiments of this utility model. It should be noted that any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model. Any other aspects not described in detail are prior art.

Claims

1. A welding structure for a chlorine liquefaction device pipe head, characterized in that: It includes a tube sheet (1) and several heat exchange tubes (2), with the heat exchange tubes (2) passing through the tube sheet (1); the length L of the tube head of the heat exchange tube (2) extending out of the tube sheet (1) is 0 to 1 mm; The tube sheet (1) is provided with a bevel (3) for connecting with the heat exchange tube (2), and the angle of the bevel (3) is 45° to 60°. The heat exchange tube (2) and the tube sheet (1) are connected by an expansion joint to form an interference fit. The groove (3) is filled with a weld (4) to fix the heat exchange tube (2) and the tube sheet (1) in place.

2. The chlorine liquefaction device pipe head welding structure according to claim 1, characterized in that: The depth of the bevel (3) is 1-2 mm.

3. The welding structure for the chlorine liquefaction unit pipe head according to claim 1, characterized in that: The length of the heat exchange tube (2) extending out of the tube sheet (1) is 0.2 to 0.8 mm.

4. The chlorine liquefaction device pipe head welding structure according to claim 1, 2, or 3, characterized in that: The bevel (3) is a V-shaped bevel.

5. The chlorine liquefaction device pipe head welding structure according to claim 1, 2, or 3, characterized in that: The interference between the heat exchange tube (2) and the hole wall of the tube sheet (1) is 0.05 to 0.15 mm.

6. The chlorine liquefaction device pipe head welding structure according to claim 1, 2, or 3, characterized in that: The weld (4) is a multi-layer, multi-pass fillet weld.

7. The chlorine liquefaction device pipe head welding structure according to claim 1, 2, or 3, characterized in that: The angle of the bevel (3) is 45° to 50°.

8. The chlorine liquefaction device pipe head welding structure according to claim 1, 2, or 3, characterized in that: The end face of the heat exchange tube (2) is a smooth and flat tube opening.

9. The chlorine liquefaction device pipe head welding structure according to claim 1, 2, or 3, characterized in that: The center distance between two adjacent heat exchange tubes (2) is not less than 1.25 times the outer diameter of the heat exchange tube (2).

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