Manufacturing and forming method of large cactus connecting pipe

Abstract

The invention discloses a manufacturing and forming method of a large cactus connecting pipe, and belongs to the technical field of connecting pipe manufacturing. Lofting and manufacturing a main connecting pipe A; lofting and manufacturing branch pipes B and C; and assembling the cactus connecting pipe by adopting an upside-down mounting method. When the middle cone of the main connecting pipe is manufactured, after numerical control blanking is conducted, a cutting point is reserved for each hole opening part, and after roundness correction of the cone is completed, the reserved cutting points are removed. When the mitre bend is manufactured, the mitre bend is manufactured in a straight pipe cutting forming mode, after numerical control blanking is conducted, an intersecting line is cut through point line cutting and rolled into a straight barrel, and then the cutting line point remaining position is cut open according to the intersecting line. The invention further provides a mitre bend cutting / welding device which is used for synchronously and respectively cutting / welding two intersecting lines on the straight barrel. According to the method, the hole opening deviation and material waste can be effectively reduced, the assembly accuracy and the construction efficiency are improved, the manufacturing period can be shortened, and the manufacturing quality is improved.

Description

Technical Field

[0001] The invention mainly relates to the technical field of pipe making, and in particular to a method for making and molding a large-scale cactus pipe. Background Art

[0002] The cactus pipe is an important pipe component in the dehydrogenation reactor. The structure of the cactus pipe is as follows: Figure 1 As shown, it includes a main pipe A, branch pipes B and branch pipes C, and branch pipes B and branch pipes C are respectively connected at both sides of the main pipe A. Because its shape is similar to a cactus, it is called a cactus pipe.

[0003] The manufacturing process of the cactus pipe is complicated, the pipe diameter is relatively large, and the dimensional accuracy requirements are high. During assembly, because the ABC pipe of the equipment extends to a height of 8.25 meters, and the flatness and distance tolerances between the ABC pipe flanges are high, the forward assembly method has a high construction height and is more difficult. Because the cactus pipe wall is thick and the diameter is large, the traditional intersection line cutting machine cannot achieve automatic cutting, and special processes are required; at the same time, the opening size on the main pipe cone must match the oblique branch pipe. At present, the manufacturing of special-shaped components such as cone openings and large pipe intersection lines relies on manual lofting, cutting grooves, welding, and assembly. The manufacturing cycle is long and the quality is difficult to guarantee. In addition, the structure of the shrimp bend is relatively special, and the cutting and welding operations during its production process are relatively inconvenient. Summary of the invention

[0004] The technical solution of the present invention aims at the technical problem that the existing technical solution is too single, and provides a solution that is significantly different from the existing technology. It mainly provides a method for making and forming a large cactus pipe, which is used to solve the technical problems mentioned in the above background technology that the existing large cactus pipe has a long manufacturing cycle and is difficult to ensure quality.

[0005] The technical solution adopted by the present invention to solve the above technical problems is: A method for manufacturing a large cactus pipe, comprising the following steps: S1. Cactus takeover simulation modeling: Use computer software to model and display samples; S2. Layout and manufacturing of main pipe A: For the middle cone, firstly layout to obtain the fan-shaped expansion diagram, then confirm the position and size of the hole to be opened on the middle cone, leave some material when cutting, and reserve at least 6 cutting points for each opening part. After the cone is rounded, remove the reserved cutting points to complete the manufacturing of the middle cone; S3. Layout and manufacturing of branch pipes B and C: The shrimp bend of branch pipe B is manufactured by cutting and forming a straight pipe. First, layout is performed according to the diameter of the center distance of the shrimp bend and the angle of each section of the shrimp bend, the length of the straight pipe and the size of the intersection line are confirmed, and the shrimp bend expansion diagram is obtained by layout; then when the shrimp bend is cut, the intersection line requires point line cutting, and the two ends are left with residual material without cutting to prevent the two ends from being unable to close during the rolling process after cutting; after cutting, rolling is performed, and the rolled shape is a straight cylinder. The points left by the cutting line are cut according to the intersection line, and the end face grooves to be assembled are ground; finally, the assembly and welding are performed directly according to the shrimp bend forming diagram to complete the production of the shrimp bend; S4. Cactus pipe forming: Use the inverted method to face the flange of the main pipe A downwards, fix the flange on the tooling with bolts and make it level, use the tooling to assemble the branch pipes B and C oblique pipes and the middle cone opening area of ​​the main pipe A respectively, and fix the branch pipes on the tooling to weld the pipe mouth intersection line to ensure the relative center distance of the three cactus flanges and the 30° inclination angle of the flange surface of the branch pipe C, and then complete the production and forming of the large cactus pipe.

[0006] Specifically, in step S1, Rhino software and CAD are used to unfold the sample.

[0007] Specifically, in step S2, the flat plate opening contour of the middle cone is determined by using a method for making a complex intersecting line pipe node, each branch pipe on the node is unfolded, and the intersection of the inner wall and outer wall intersection lines of the branch pipe is used as a reference point to select the inner wall line and the outer wall line of the through-mouth. The inner wall line is selected in the toe area and the outer wall line is selected in the root area to obtain the through-mouth shape; the lowest point of the through-mouth is used as the starting point, and the steel plate is divided into N equal parts to cut the through-mouth.

[0008] Furthermore, in step S3, for the oblique tube, the cutting size is confirmed according to the diameter and angle of the oblique tube; when cutting the oblique tube, point line cutting is adopted on the intersection line side; after the rolling and welding is completed, the excess material at the intersection line is cut off.

[0009] Furthermore, in step S4, the installation orientation of the nozzle assembly tooling is confirmed according to the relative positions of the ABC nozzle flanges, and the tooling is spot welded to the assembly platform, wherein the installation angle of the branch pipe C nozzle assembly tooling is consistent with the C nozzle flange.

[0010] As an optimization of the above scheme, in step S3, the cutting and welding of the straight cylinder is achieved by a shrimp-bend cutting / welding device, and the structure of the shrimp-bend cutting / welding device is as follows: it includes a fixed cylinder, and a first annular groove and a second annular groove corresponding to two intersecting lines on the straight cylinder are provided on the inner surface of the fixed cylinder, respectively; a rotatable rotating ring coaxially arranged with the fixed cylinder is clamped on the inner surface of the fixed cylinder, and a first moving rod and a second moving rod are slidably connected to the rotating ring, and a first processing head and a first limit block extending in the first annular groove are installed on the first moving rod, and a second processing head and a second limit block located in the second annular groove are detachably installed on the second moving rod; a driving mechanism for driving the rotating ring to rotate is also installed on the fixed cylinder.

[0011] Furthermore, the first moving rod and the second moving rod are respectively located at two opposite sides of the rotating ring, and the moving directions of the first moving rod and the second moving rod are parallel to the axis of the fixed cylinder.

[0012] Furthermore, the driving mechanism includes a gear ring arranged on the outer ring surface of the rotating ring and a gear driven by a motor, and a notch is opened on the fixed cylinder to expose the gear ring, and the gear meshes with the gear ring at the notch.

[0013] Furthermore, during cutting, the first processing head and the second processing head use cutting tools to drive the rotating ring to rotate, and then the first moving rod and the second moving rod rotate accordingly. Under the limiting effect of the first annular groove on the first limit block and the limiting effect of the second annular groove on the second limit block, the moving trajectory of the first processing head conforms to the shape of the first annular groove, and the moving trajectory of the second processing head conforms to the shape of the second annular groove, thereby realizing the synchronous cutting of the two intersecting lines on the straight cylinder body; during welding, the first processing head and the second processing head use welding tools to keep the middle section of the straight cylinder body stationary, change the shape of the upper and lower sections, and then start the device to realize the synchronous welding of the three sections of the shrimp bend, thereby completing the forming of the shrimp bend.

[0014] Furthermore, the mounting ends of the first processing head and the second processing head are both connected with electric telescopic rods, and the electric telescopic rods are used to drive the corresponding processing heads to move along the slope of the corresponding annular groove to adapt to straight cylinders with different pipe diameters.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The present invention utilizes computer software to carry out modeling and unfolding of cactus pipes, realizes CNC cutting, completes intersecting line forming and pre-opening of pipes before rolling through modeling, can effectively reduce opening deviation and material waste, improve assembly accuracy and construction efficiency, thus shortening the manufacturing cycle and improving production quality. When manufacturing the middle cone of the main pipe, the present invention reserves at least 6 cutting points for each opening part after CNC blanking, and removes the reserved cutting points after the cone is rounded. Compared with the method of manually cutting the intersection line after forming in the prior art, the position accuracy and dimensional accuracy of the intersection line can be guaranteed, and the efficiency is higher. Compared with the method of directly cutting the opening part after blanking and then rolling to form, the problem of straight edge formation due to uneven force during the rolling process can be avoided. Thereby, the manufacturing cycle can be shortened and the manufacturing quality can be improved. The present invention adopts the straight tube cutting and forming method to make the shrimp bend. After CNC blanking, the intersection line is cut by point line, which is convenient for indicating the trajectory of subsequent cutting and can also reduce the work intensity of subsequent cutting. The two ends are left with surplus material without cutting to prevent the situation that the two ends cannot be closed during the rolling process after cutting. After rolling into a straight cylinder, the cutting line is cut according to the intersection line, and no more setting out is required. It can be directly assembled and welded according to the shrimp bend forming diagram. While accelerating the production efficiency, the forming quality of the shrimp bend is guaranteed. The present invention adopts the inverted assembly method to assemble the cactus pipe, that is, the main pipe A, branch pipe B and branch pipe C are fixed on the tooling with their flanges facing downwards, and the tooling is used to respectively assemble the branch pipes B and C obliquely inserted into the cone opening area in the middle of the main pipe A, and then the intersection lines are welded. Compared with the forward assembly method, the construction height can be greatly reduced, the construction and measurement are convenient, the installation efficiency is greatly improved, the tooling material cost is reduced, and the safety hazards existing in the construction process are also reduced. The optimized solution of the present invention provides a shrimp bend cutting / welding device, which drives two processing heads to work synchronously through the rotation of a rotating ring, and at the same time, through the limiting effect of two annular grooves matching the target intersection line, the two processing heads are respectively moved along the trajectory matching the target intersection line, so that the two processing heads can finally synchronously perform cutting / welding processing on the two intersection lines on the straight cylinder. During the shrimp bend production process, when cutting, the processing head uses a cutting tool; when welding, the cutting tool is replaced with a welding tool, so that the cutting and welding processing of the shrimp bend material can be completed by one device, which is convenient to use, can improve work efficiency, and is conducive to shortening the manufacturing cycle of the cactus pipe and improving the production quality. The present invention will be explained in detail below with reference to the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of the structure that the cactus takes over; Figure 2 and Figure 3 This is a simulation modeling diagram of the cactus pipe connection in the present invention, wherein: Figure 2 Take over the overall picture for the cactus, Figure 3 Take over the split diagram for the cactus; Figure 4 This is an expanded view of the middle cone of the main pipe A in the embodiment; Figure 5 A schematic diagram of the cutting reservation of the middle cone of the main pipe A; Figure 6 This is the expansion diagram of the shrimp bend of branch pipe B; Figure 7 The following are the forming diagrams of the shrimp bend of branch pipe B, wherein Figure (a) is a schematic diagram of a straight cylinder with a cutting line, and Figure (b) is a forming diagram of the assembly welding; Figure 8 This is the development diagram of the oblique insertion of branch pipe C; Fig. 9 This is a schematic diagram of the cactus tube inverted installation; Fig.10 It is a schematic diagram of the three-dimensional structure of the shrimp bend cutting / welding device in the second embodiment of the present invention; Fig.11 for Fig.10 A longitudinal cross-sectional view of the shrimp bend cutting / welding device; Fig.12 for Fig.11 A schematic diagram of the structure of the middle region A; Fig.13 for Fig.11 A schematic diagram of the structure of the middle region B; Fig.14 It is a longitudinal cross-sectional view of the shrimp bend cutting / welding device in the third embodiment of the present invention; Fig.15 It is a schematic diagram of the application status of the shrimp bend cutting / welding device in the second embodiment of the present invention.

[0017] Reference numerals: 1. Fixed cylinder; 11. First annular groove; 12. Second annular groove; 13. Notch; 2. First moving rod; 3. First processing head; 4. Rotating ring; 5. Gear; 6. Motor; 7. Second moving rod; 8. Second limit block; 9. Second processing head; 10. First limit block; 20. Electric telescopic rod. DETAILED DESCRIPTION

[0018] To facilitate understanding of the present invention, the present invention will be described more comprehensively below with reference to the relevant drawings. Several embodiments of the present invention are given in the drawings, but the present invention can be implemented in different forms and is not limited to the embodiments described in the text. On the contrary, these embodiments are provided to make the content disclosed in the present invention more thorough and comprehensive.

[0019] It should be noted that when an element is referred to as being "fixed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used in this article are for illustrative purposes only.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly connected by technicians in the technical field to which the present invention belongs. The terminology used in the specification of the present invention is for the purpose of describing specific embodiments and is not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0021] Embodiment 1: A method for manufacturing a large cactus pipe, comprising the following steps: S1. Cactus takeover simulation modeling: The main pipe specifications of the cactus pipe are DN1730 / DN2692*34, and the branch pipe specifications are DN1860*25 and DN906*32. The main and branch pipes are connected. Use Rhino software and CAD to develop and draw samples. Figure 2 and Figure 3 shown.

[0022] S2. Layout and manufacturing of main pipe A: The main pipe A not only involves the lofting of the cone, but also considers whether the size of the opening on the cone matches the oblique insert, including whether it affects the rolling of the cone. Directly opening the hole when cutting the material saves the subsequent process of opening and marking the hole, and reduces the manufacturing cycle.

[0023] (1) First, confirm the diameters of the large and small openings, thickness and height of the cone in the middle of the main pipe A. Loft the cone based on the cone mid-diameter. After unfolding, the shape should be a fan-shaped. The length of the small arc of the fan-shaped is equal to the circumference of the cone's small opening mid-diameter, and the length of the large arc of the fan-shaped is equal to the circumference of the cone's large opening mid-diameter. The side length of the fan-shaped should be equal to the length of the hypotenuse of the cone. According to the size of the cone after unfolding and the conventional plate pair size of the steel plate, the number of longitudinal and circumferential seams of the cone can be confirmed.

[0024] (2) Secondly, confirm the pipe opening diameter, oblique insertion angle and relative position of branch pipes B and C where branch pipes B and C are connected to the middle cone of main pipe A, so as to confirm the size of the flat plate opening of the middle cone by lofting. The unfolded diagram of the middle cone is shown in the figure below. Figure 4 shown.

[0025] (3) Adopt the method of making complex intersecting line pipe nodes, unfold each branch pipe on the node, take the intersection of the inner wall and outer wall of the branch pipe as the reference point, select the inner wall line and outer wall line of the through-mouth, select the inner wall line in the toe area and the outer wall line in the root area to obtain the through-mouth shape; take the lowest point of the through-mouth as the starting point, divide the steel plate into N equal parts, and cut the through-mouth.

[0026] (4) When cutting, the fan-shaped plate is cut according to the given size. However, since the openings of branch pipes B and C are relatively large, the force is uneven during the rolling process, which easily forms a straight edge phenomenon and is difficult to eliminate. Figure 5 As shown, the openings of branch pipes B and C require some space for cutting, with a reserved length of 100 mm. At least 6 cutting points are reserved for each opening. After the cone is rounded, the reserved cutting points are removed.

[0027] (5) Cut and make the middle cone, upper cone, upper pipe and lower pipe respectively, then weld and connect the parts and connect a flange to complete the production of main pipe A. The equipment flange of main pipe A is made of S31008 material. The A pipe flange, the corresponding pipe and cone (S31008 part) are assembled and fixed by spot welding. The misalignment meets the relevant requirements of the standard. E310-15 welding rod is used for welding. Non-destructive testing is performed after welding. The cone and the middle cone (material Q345R) of the S31008 part are assembled. The misalignment meets the requirements of the standard specification. The welding material is ENi6152.

[0028] S3. Lofting and manufacturing of branch pipes B and C: (1) Manufacturing of shrimp bend The shrimp bend of branch pipe B is formed by cutting straight pipes. According to the diameter of the shrimp bend center distance and the angle of each shrimp bend, the straight pipe length and the intersection line size are confirmed. The shrimp bend expansion diagram is shown as follows: Figure 6 When the shrimp is bent, the intersection line is required to be cut at points, and 50mm is left at both ends to prevent the two ends from being unable to close during the rolling process after being cut.

[0029] Roll according to the shrimp bend expansion diagram, the rolled shape is a straight cylinder, cut the cutting line points according to the intersection line, and grind the end face groove to be assembled. No need to set out, just press Figure 7 The middle shrimp bend forming diagram can be used for assembly welding. During the welding process, a support plate is required around the weld to prevent welding deformation.

[0030] (2) Lofting of oblique pipe The cone between branch pipes B, C and main pipe A adopts the oblique insertion method. The cutting size is confirmed according to the diameter and angle of the oblique insertion pipe. The expansion diagram of the oblique insertion pipe of branch pipe C is shown in the figure below. Figure 8 shown.

[0031] When cutting the material of the oblique pipe, the intersection line side is cut with points and lines, otherwise it is impossible to roll. After the rolling and welding is completed, the excess material at the intersection line is cut off.

[0032] (3) Assembly of branches B and C Cut materials to make shrimp bends, cones, middle pipes, and oblique inserts respectively, then weld and connect the parts, and connect a flange to complete the production of branch pipe B; cut materials to make cones, middle pipes, and oblique inserts respectively, then weld and connect the parts, and connect a flange to complete the production of branch pipe C. SA387 GR.11.CL.2 The transition section (cone) is assembled with the corresponding branch pipe B and C pipe mouth flanges, spot welded, and the weld is preheated before welding. The preheating temperature shall not be lower than 95°C. After welding, the transition section and flange are heat treated as a whole. After the heat treatment is completed, the flange sealing surface is machined to the size required by the drawing. Assemble the subsequent pipes and shrimp bends according to the requirements of the drawing.

[0033] S4, Cactus tube forming: (1) First, confirm the dimensions of the ABC pipe mouth flanges, and make the corresponding pipe mouth assembly tooling according to the dimensions, with 6 bolt holes evenly distributed on the tooling.

[0034] (2) Determine the installation orientation of the nozzle assembly tooling according to the relative positions of the ABC nozzle flanges, and spot weld the tooling to the assembly platform. The installation angle of the branch pipe C nozzle assembly tooling should be consistent with the C nozzle flange, and measure the distance, angle, flatness and tolerance requirements between each tooling.

[0035] (3) If Fig. 9 As shown, the inverted installation method is adopted, and the main pipe A is inserted upside down on the tooling by a crane with the flange opening facing downwards, and the flange is fixed on the tooling with bolts and leveled; (4) Insert branch pipe B and branch pipe C upside down on the corresponding tooling through a crane, and use the tooling to assemble branch pipes B and C obliquely and the middle cone opening area of ​​main pipe A. At the same time, fix the branch pipes on the tooling for pipe mouth intersection welding to ensure the relative center distance dimensions of the three cactus flanges (the center distance from pipe mouth A to pipe mouth C is 3300±3, and the center distance from pipe mouth B to pipe mouth is 3600±3) and the 30° inclination angle of the flange surface of pipe mouth C.

[0036] Embodiment 2: This embodiment differs from Embodiment 1 in that: In the manufacturing process of the shrimp bend, Fig.10 The device shown can realize the cutting and welding of the straight cylinder. Please refer to the attached Figure 10-13 The structure of the shrimp bend cutting / welding device specifically includes: A fixed cylinder 1, the inner surface of which is provided with a first annular groove 11 and a second annular groove 12 corresponding to two intersecting lines on the straight cylinder body, respectively, and the first annular groove 11 and the second annular groove 12 are symmetrically arranged; two opposite sides of the fixed cylinder 1 are provided with notches 13; The rotating ring 4 is rotatably mounted on the inner surface of the fixed cylinder 1, and the rotating ring 4 is coaxially arranged with the fixed cylinder 1; a gear ring is arranged on the outer ring surface of the rotating ring 4, and a part of the gear ring can be seen through the notch 13; The connecting rod includes a first moving rod 2 and a second moving rod 7, both of which are slidably connected to the rotating ring 4; the first moving rod 2 and the second moving rod 7 are respectively located at two opposite sides of the rotating ring 4, and the moving directions of the first moving rod 2 and the second moving rod 7 are parallel to the axis of the fixed cylinder 1; and the first moving rod 2 is provided with a first stopper 10 extending in the first annular groove 11, and the second moving rod 7 is detachably provided with a second stopper 8 located in the second annular groove 12; The processing head includes a first processing head 3 and a second processing head 9, which are detachably mounted on the first moving rod 2 and the second moving rod 7 respectively; the processing head uses a cutting tool, a welding tool (welding gun, etc.); The driving mechanism is arranged outside the fixed cylinder 1 and comprises a gear 5 driven by a motor 6 . The gear 5 meshes with the gear ring on the rotating ring 4 at the notch 13 .

[0037] During the application, when cutting, the first processing head 3 and the second processing head 9 use cutting tools to hoist the rolled straight cylinder to the inner side of the fixed cylinder 1, and make the two coaxially arranged, such as Fig.15 As shown in (a). After the straight cylinder is supported, the rotating ring 4 is driven to rotate, and the first moving rod 2 and the second moving rod 7 rotate accordingly. Under the limiting effect of the first annular groove 11 on the first limiting block 10 and the limiting effect of the second annular groove 12 on the second limiting block 8, the moving trajectory of the first processing head 3 conforms to the shape of the first annular groove 11, and the moving trajectory of the second processing head 9 conforms to the shape of the second annular groove 12, so as to realize the synchronous cutting of the two intersecting lines on the straight cylinder.

[0038] During welding, the first processing head 3 and the second processing head 9 use welding tools to keep the middle section of the straight cylinder unchanged and change the shape of the upper and lower sections, such as Fig.15 After the straight cylinder is supported, the device is started and operated as above to realize the simultaneous welding of the three sections of the shrimp bend, thus completing the forming of the shrimp bend.

[0039] The rest is the same as the first embodiment.

[0040] Embodiment 3: This embodiment differs from Embodiment 2 in that: like Fig.14As shown, the mounting ends of the first processing head 3 and the second processing head 9 are both connected with an electric telescopic rod 20, which is used to drive the corresponding processing head to move along the slope of the corresponding annular groove to adapt to straight cylinders with different pipe diameters.

[0041] The rest is the same as the second embodiment.

[0042] The above is an exemplary description of the present invention in combination with the accompanying drawings. It is obvious that the specific implementation of the present invention is not limited to the above-mentioned method. As long as such non-substantial improvements are made by adopting the method concept and technical solution of the present invention, or the concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. A method for manufacturing a large cactus pipe, characterized in that: The steps include: S1. Cactus takeover simulation modeling: Use computer software to model and display samples; S2. Layout and manufacturing of main pipe A: For the middle cone, firstly layout to obtain the fan-shaped expansion diagram, then confirm the position and size of the hole to be opened on the middle cone, leave some material when cutting, and reserve at least 6 cutting points for each opening part. After the cone is rounded, remove the reserved cutting points to complete the production of the middle cone; S3. Layout and manufacturing of branch pipes B and C: The shrimp bend of branch pipe B is manufactured by cutting and forming a straight pipe. First, layout is performed according to the diameter of the center distance of the shrimp bend and the angle of each section of the shrimp bend, the length of the straight pipe and the size of the intersection line are confirmed, and the shrimp bend expansion diagram is obtained by layout; then when the shrimp bend is cut, the intersection line requires point line cutting, and the two ends are left with residual material without cutting to prevent the two ends from being unable to close during the rolling process after cutting; after cutting, rolling is performed, and the rolled shape is a straight cylinder. The points left by the cutting line are cut according to the intersection line, and the end face grooves to be assembled are ground; finally, the assembly and welding are performed directly according to the shrimp bend forming diagram to complete the production of the shrimp bend; S4. Cactus pipe forming: Use the inverted method to face the flange of the main pipe A downwards, fix the flange on the tooling with bolts and make it level, use the tooling to assemble the branch pipes B and C oblique pipes and the middle cone opening area of ​​the main pipe A respectively, and fix the branch pipes on the tooling to weld the pipe mouth intersection line to ensure the relative center distance of the three cactus flanges and the 30° inclination angle of the flange surface of the branch pipe C, and then complete the production and forming of the large cactus pipe.

2. The method for manufacturing a large cactus pipe according to claim 1, characterized in that: In step S1, Rhino software and CAD are used to unfold the sample.

3. The method for manufacturing a large cactus pipe according to claim 1, characterized in that: In step S2, the flat plate opening contour of the middle cone is determined by the method of making a complex intersecting line pipe node, each branch pipe on the node is unfolded, and the intersection of the inner wall and outer wall intersection lines of the branch pipe is used as the reference point. The inner wall line and the outer wall line of the through-mouth are selected, the inner wall line is selected in the toe area, and the outer wall line is selected in the root area to obtain the through-mouth shape; the lowest point of the through-mouth is used as the starting point, and the steel plate is divided into N equal parts to cut the through-mouth.

4. The method for manufacturing a large cactus pipe according to claim 1, characterized in that: In step S3, for the oblique tube, the cutting size is confirmed according to the diameter and angle of the oblique tube; when cutting the oblique tube, point-line cutting is adopted on the intersection line side; after the rolling and welding is completed, the excess material at the intersection line is cut off.

5. The method for manufacturing a large cactus pipe according to claim 1, characterized in that: In step S4, the installation orientation of the nozzle assembly tooling is determined according to the relative positions of the ABC nozzle flanges, and the tooling is spot welded to the assembly platform, wherein the installation angle of the branch pipe C nozzle assembly tooling is consistent with the C nozzle flange.

6. A method for manufacturing a large cactus pipe according to any one of claims 1 to 5, characterized in that: In step S3, the straight cylinder is cut and welded by a shrimp-bend cutting / welding device, the structure of which is as follows: it comprises a fixed cylinder (1), the inner surface of which is provided with a first annular groove (11) and a second annular groove (12) respectively corresponding to two intersecting lines on the straight cylinder, the inner surface of which is provided with a rotating ring (4) which is rotatable and coaxially arranged with the fixed cylinder (1), the rotating ring (4) being slidably connected with a first moving rod (2) and a second moving rod (7), the first moving rod (2) being provided with a first processing head (3) and a first limit block (10) extending into the first annular groove (11), the second moving rod (7) being detachably provided with a second processing head (9) and a second limit block (8) located in the second annular groove (12); the fixed cylinder (1) is also provided with a driving mechanism for driving the rotating ring (4) to rotate.

7. The method for manufacturing a large cactus pipe according to claim 6, characterized in that: The first moving rod (2) and the second moving rod (7) are respectively located at two opposite sides of the rotating ring (4); the moving directions of the first moving rod (2) and the second moving rod (7) are parallel to the axis of the fixed cylinder (1).

8. The method for manufacturing a large cactus pipe according to claim 6, characterized in that: The driving mechanism comprises a gear ring arranged on the outer ring surface of a rotating ring (4) and a gear (5) driven by a motor (6); a notch (13) for exposing the gear ring is provided on the fixed cylinder (1); and the gear (5) meshes with the gear ring at the notch (13).

9. The method for manufacturing a large cactus pipe according to claim 6, characterized in that: During cutting, the first processing head (3) and the second processing head (9) use cutting tools to drive the rotating ring (4) to rotate, and then the first moving rod (2) and the second moving rod (7) rotate accordingly. Under the limiting effect of the first annular groove (11) on the first limiting block (10) and the limiting effect of the second annular groove (12) on the second limiting block (8), the moving trajectory of the first processing head (3) conforms to the shape of the first annular groove (11), and the moving trajectory of the second processing head (9) conforms to the shape of the second annular groove (12), thereby realizing synchronous cutting of two intersecting lines on the straight cylinder; during welding, the first processing head (3) and the second processing head (9) use welding tools to keep the middle section of the straight cylinder stationary, change the shape of the upper and lower sections, and then start the device to realize synchronous welding of the three sections of the shrimp bend, thereby completing the forming of the shrimp bend.

10. The method for manufacturing a large cactus pipe according to claim 6, characterized in that: The mounting ends of the first processing head (3) and the second processing head (9) are both connected to an electric telescopic rod (20), and the electric telescopic rod (20) is used to drive the corresponding processing head to move along the slope of the corresponding annular groove to adapt to straight tubes with different pipe diameters.

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