Splicing construction method for pressure vessel shell

Abstract

The invention belongs to the technical field of pressure tank production, and particularly relates to a pressure vessel shell splicing construction method which comprises the following steps: vertically placing a barrel on an assembly platform, placing an upper seal head on the barrel, taking two fixing points on two sides of the barrel, and aligning welding seams at the fixing points; a material receiving tool is arranged at the weld joint of the barrel and the end socket, the position, with obvious misalignment, of a butt joint of the weld joint is supported and adjusted through the material receiving tool, it is guaranteed that the butt joint alignment tolerance meets the design requirement, and the weld joint is fixed in a spot welding mode after supporting and adjusting are completed; after the welding seam is fixed through spot welding, the material receiving tool is removed, argon arc welding is adopted for bottoming of the whole welding seam, and submerged arc welding is adopted for filling and capping; similarly, the lower sealing head and the cylinder are welded. According to the construction method, the manufacturing difficulty of butt joint assembly of the end socket and the barrel of the pressure vessel is reduced, the construction method is simpler and easier to operate, and the manufacturing efficiency and the manufacturing precision of butt joint between the end socket and the barrel are improved.

Description

Technical Field

[0001] This invention belongs to the field of pressure vessel manufacturing technology, specifically relating to a method for assembling and constructing pressure vessel shells. Background Technology

[0002] In modern industry, pressure vessels, as special equipment used for storing, transporting, or reacting gases or liquids under pressure, are widely used in many industries such as petrochemicals, energy, pharmaceuticals, food, and metallurgy. Their safety performance is directly related to the stable operation of the production process and the safety of personnel and property; therefore, extremely high requirements are placed on the manufacturing quality of pressure vessels.

[0003] As the core pressure-bearing component that withstands internal or external pressure, the structural integrity and welding quality of the pressure vessel shell are crucial to ensuring the safe operation of the vessel. The shell is typically assembled from several cylindrical sections, heads, and other components through welding. The quality of the assembly directly determines the overall strength, sealing performance, and service life of the pressure vessel.

[0004] Traditional pressure vessel shell assembly methods often face several challenges in practice. Firstly, the alignment accuracy and misalignment control are difficult during the assembly stage of shell components (such as sections and heads). Due to manufacturing errors in the components themselves, stress deformation during hoisting, and a strong reliance on manual adjustment experience, the assembled shell is prone to significant roundness deviations, and misalignment at longitudinal and circumferential welds may exceed standard allowable ranges. This not only increases the difficulty of subsequent welding but may also generate significant welding stress and deformation after welding, affecting the structural stability of the shell. Summary of the Invention

[0005] The technical problem to be solved by this invention is the adjustment of the misalignment of the weld seam between the pressure vessel shell and the head.

[0006] The technical solution adopted by the present invention to solve the aforementioned problem is as follows: A method for assembling a pressure vessel shell comprises the following steps: Step 1: Based on the end caps at both ends of the processed pressure vessel, measure the circumference and diameter of the opening of the upper and lower end caps respectively. Step 2: The cylinder blanking is carried out according to the circumference of the upper and lower end caps as the unfolding and cutting dimensions. The cylinder steel plate is cut and the upper and lower end marks are marked on the surface of the cylinder steel plate to facilitate the subsequent splicing of the corresponding end caps. Step 3: Place the cut cylindrical steel plate into a rolling mill for round rolling, and check the roundness of the cylinder with a sheet metal template. After passing the test, spot weld the longitudinal seam of the cylinder to fix it. Step 4: The longitudinal seam of the cylinder is constructed by argon arc welding for the root pass and submerged arc welding for the fill and cover pass. Step 5: Design and fabricate the receiving fixtures for the cylinder and the end cap; Step 6: Place the cylinder upright on the assembly platform, place the upper end cap on the cylinder, and take two fixing points on both sides of the cylinder to align the weld at the fixing points. Step 7: Move and hoist the receiving fixture and place it at the weld between the cylinder and the head. Use the receiving fixture to support and adjust the position where there is obvious misalignment at the weld joint to ensure that the misalignment meets the design requirements. After the support and adjustment are completed, spot weld the weld to fix it. Step 8: After the weld is spot welded and fixed, loosen the bolts, then remove the receiving fixture, and perform argon arc welding for the root pass and submerged arc welding for the fill and cover pass of the weld. Step nine: Following steps six through eight, assemble and weld the lower end cap and the cylinder.

[0007] Compared with the prior art, the present invention employing the above structure has the following advantages: This construction method reduces the difficulty of assembling the pressure vessel head and shell, making the construction method simpler and easier to operate, and improving the efficiency and accuracy of the connection between the head and shell.

[0008] As a preferred option, a further technical solution to the above structure is: Preferably, the receiving fixture includes two annular steel rings arranged at an interval, and several connecting plates are uniformly welded between the two annular steel rings to form a whole. Nuts are uniformly fixed to the opposite sides of the two annular steel rings, and bolts are installed in the nuts. The ends of the bolts abut against the surfaces of the cylinder and the end cap.

[0009] Preferably, in step seven, the misalignment is adjusted by rotating the bolt, so that the bolt end applies pressure to the surface of the cylinder or the upper end cap, causing the cylinder or the upper end cap ring to deform and thus achieve complete alignment.

[0010] Preferably, the nuts fixed to the upper annular steel ring correspond one-to-one with the nuts fixed to the lower annular steel ring, and the corresponding nuts are respectively set on both sides of the connecting plate. Attached Figure Description

[0011] Figure 1 This is an overall structural diagram of the welding and fixing scheme of the present invention; Figure 2 This is a schematic diagram of the head size measurement of the present invention; Figure 3 This is an unfolded schematic diagram of the cylindrical steel plate of the present invention; Figure 4 This is a schematic diagram of the cylinder rolling process of the present invention; Figure 5 This is a drawing of the receiving tooling for this invention; Figure 6This is a schematic diagram of the connection between the cylinder body and the upper end cap of the present invention; Figure 7 This is a schematic diagram of the installation of the receiving fixture and the adjustment of the alignment using the receiving fixture according to the present invention.

[0012] The markings in the diagram are as follows: 1. Upper end cap; 2. Cylinder body; 3. Receiving fixture; 4. Assembly platform; 5. Upper pressure roller; 6. Lower pressure roller; 7. Fixing point; 8. Weld seam; 11. Circumference of the opening; 12. Diameter of the opening; 21. Cylinder body steel plate; 31. Annular steel ring; 32. Nut; 33. Bolt; 34. Connecting plate; 35. Lifting lug. Detailed Implementation

[0013] The present invention will be further described below with reference to embodiments, which are intended only to provide a better understanding of the invention. Therefore, the examples given do not limit the scope of protection of the present invention.

[0014] See appendix Figures 1-7 This invention provides a method for assembling and constructing a pressure vessel shell, comprising the following steps: Step 1, refer to Figure 2 As shown, based on the end caps at both ends of the processed pressure vessel, the circumference 11 and diameter 12 of the opening of the upper and lower end caps are measured respectively.

[0015] Step 2, refer to Figure 3 As shown, the cylindrical body 2 is cut according to the circumference 11 of the upper and lower end caps as the unfolded cutting dimensions. The cylindrical body steel plate 21 is cut and marked on the surface of the cylindrical body steel plate 21 to facilitate the subsequent splicing of the corresponding end caps. In actual engineering, the circumference of the upper end cap 1 and the lower end cap are usually the same. Measuring the circumference separately is only to clarify the manufacturing deviation.

[0016] Step 3: Place the cut cylindrical steel plate 21 into a rolling mill for rounding, and check the roundness of the cylinder using a sheet metal template. After passing the check, spot weld the longitudinal seam of the cylinder 2 to secure it. See also Figure 4 The rolling bed includes an upper pressure roller 5 and two lower pressure rollers 6. When the cylindrical steel plate 21 is rolled, the cylindrical steel plate 21 is fed into the pressure rollers through the conveying mechanism, and the forming curvature of the cylindrical steel plate 21 is adjusted by dynamically adjusting the upper pressure roller 5.

[0017] Step 4: Argon arc welding is used for the root pass of the longitudinal seam of cylinder 2, and submerged arc welding is used for the filling and covering.

[0018] Step 5: Design and fabricate the receiving fixture 3 for the cylinder 2 and the end cap. (See reference...) Figure 5 , Figure 7The receiving fixture 3 includes two annular steel rings 31 arranged at an interval, coaxially positioned. Several connecting plates 34 are evenly welded between the two annular steel rings 31, assembling them into a single unit. Nuts 32 are evenly fixed to the opposite sides of the two annular steel rings 31, with bolts 33 installed in the nuts 32. The ends of the bolts 33 abut against the surfaces of the cylinder 2 and the upper end cap 1. Lifting lugs 35 are also fixed to the top surface of the annular steel rings 31 for horizontal lifting of the receiving fixture 3. Optionally, the nuts 32 fixed to the upper annular steel ring 31 correspond one-to-one with the nuts 32 fixed to the lower annular steel ring 31, with the corresponding nuts 32 respectively located on both sides of the connecting plates 34.

[0019] Step 6: Place the cylinder 2 upright on the assembly platform 4, place the upper end cap 1 on the cylinder 2, and take two fixing points 7 on both sides of the cylinder 2 to align the weld 8 at the fixing points 7. See Figure 6 .

[0020] Step 7: Move and hoist the receiving fixture 3 and place it at the weld 8 between the cylinder 2 and the upper head 1. Use the receiving fixture 3 to support and adjust the area where there is obvious misalignment at the weld joint, ensuring that the misalignment of weld 8 meets the design requirements. After adjustment, insert a welding tool between the two annular steel rings 31 and spot weld the weld 8 area to fix it. For details, see [link to details]. Figure 7 The receiving fixture 3 is fixed to the cylinder 2 by rotating the bolt 33; the bolt 33 is further rotated so that the end of the bolt 33 applies pressure to the surface of the cylinder 2 or the upper end cap 1, so that the rim of the cylinder 2 or the upper end cap 1 is deformed, thereby achieving complete alignment and eliminating obvious misalignment.

[0021] Step 8: After the weld seam is fixed by spot welding, loosen bolt 33, then remove the receiving fixture 3, and perform argon arc welding for the root pass of weld seam 8, followed by submerged arc welding for filling and covering.

[0022] Step 9: Following steps 6 to 8, assemble and weld the lower end cap and the cylinder 2.

[0023] The beneficial effects of the present invention are as follows: The construction method provided by the present invention reduces the manufacturing difficulty of the assembly of the pressure vessel head and the cylinder, makes the construction method simpler and easier to operate, and improves the manufacturing efficiency and accuracy of the connection between the head and the cylinder.

[0024] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the present invention. All equivalent changes made based on the description and drawings of the present invention are included within the scope of the present invention.

Claims

1. A method for constructing a pressure vessel shell assembly, characterized in that, Follow these steps: Step 1: Based on the end caps at both ends of the processed pressure vessel, measure the circumference (11) and diameter (12) of the upper end cap (1) and the lower end cap respectively; Step 2, the cylinder (2) is cut according to the circumference (11) of the upper end cap (1) and the lower end cap as the size for unfolding and cutting. The cylinder steel plate (21) is cut and the upper and lower end marks are marked on the surface of the cylinder steel plate (21) to facilitate the subsequent splicing of the corresponding end caps. Step 3: Place the cut cylindrical steel plate (21) into the rolling machine for round rolling, and use a sheet metal template to check the roundness of the cylindrical body (2). After passing the test, spot weld the longitudinal seam of the cylindrical body (2) to fix it. Step 4: The longitudinal seam of the cylinder (2) is argon arc welded for the root pass and submerged arc welded for the fill and cover pass. Step 5: Design and manufacture the receiving fixture (3) for the cylinder (2) and the end cap; Step 6: Place the cylinder (2) upright on the assembly platform (4), place the upper end cap (1) on the cylinder (2), and take two fixing points (7) on both sides of the cylinder (2) so that the weld (8) is aligned at the fixing points (7); Step 7: Move and hoist the receiving fixture (3) and place it at the weld (8) between the cylinder (2) and the upper head (1). Use the receiving fixture (3) to support and adjust the position where there is obvious misalignment at the weld joint, so as to ensure that the misalignment meets the design requirements. After the adjustment is completed, spot weld the weld (8) to fix it. Step 8: After the weld is spot welded and fixed, loosen the bolt (33), then remove the receiving fixture (3), and use argon arc welding to perform the root pass of the weld (8), and submerged arc welding to perform the fill and cover pass. Step 9: Following steps 6 to 8, assemble and weld the lower end cap and the cylinder (2).

2. The pressure vessel shell splicing construction method according to claim 1, characterized in that, The receiving fixture (3) includes two annular steel rings (31) arranged at intervals. Several connecting plates (34) are welded evenly between the two annular steel rings (31) to form a whole. Nuts (32) are evenly fixed to the opposite sides of the two annular steel rings (31). Bolts (33) are installed in the nuts (32). The ends of the bolts (33) abut against the surfaces of the cylinder (2) and the upper end cap (1).

3. The pressure vessel shell splicing construction method according to claim 2, characterized in that, In step seven, the misalignment is adjusted by rotating the bolt (33) so that the end of the bolt (33) applies pressure to the surface of the cylinder (2) or the upper end cap (1) to deform the opening of the cylinder (2) or the upper end cap (1) so that they are completely aligned.

4. The pressure vessel shell splicing construction method according to claim 2, characterized in that, The nuts (32) fixed to the upper annular steel ring (31) correspond one-to-one with the nuts (32) fixed to the lower annular steel ring (31), and the corresponding nuts (32) are respectively set on both sides of the connecting plate (34).

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