Method for rigidly connecting joints of variable-diameter steel pipes in limited space

Abstract

The invention belongs to the field of steel structure design and construction, and particularly relates to a variable-diameter steel pipe rigid connection joint method in a limited space, which comprises the following steps: placing a large-diameter steel pipe in the limited space, penetrating a small-diameter steel pipe from the other side of the limited space, and keeping the axes of the two pipes consistent; scanning modeling and stress analysis are carried out, and the specification, the size and the number of connecting components are determined; connecting components are subjected to numerical control machining; positioning and welding the annular stiffening plates; positioning and welding the sealing annular plate; positioning and welding the guide plate; blowing and filling a filling material; and checking and accepting. According to the method, in a limited space, according to the conditions of specifications, sizes, relative offset positions and the like of large-diameter and small-diameter steel pipes in the current situation, a 3D scanning and numerical control cutting blanking mode is adopted, blanking is conducted in advance in a factory, and field assembly and installation are conducted, so that the steel pipes with the two diameters are connected, and a reliable rigid connection joint is formed.

Description

Technical Field

[0001] The invention belongs to the field of steel structure installation design and construction, and in particular relates to a method for rigidly connecting nodes of variable-diameter steel pipes in a confined space. Background Art

[0002] In pipeline engineering, the connection method of steel pipes directly affects the stability and safety of the entire pipeline network. For the connection of variable diameter steel pipes, the methods commonly used in engineering practice include flange connection and welding connection of reducer joints. Both of these connection methods are carried out outside the pipe, and they each have specific application scenarios and technical requirements.

[0003] The flange connection has a simple structure, is easy to install and disassemble, and can adapt to certain pipe deformation. However, the flange connection requires sufficient space to place the flange and bolts, and the tightening force of the bolts needs to be guaranteed, so an open construction surface is required during construction. The welded connection of the reducer has good sealing and stability and can withstand higher pressure. However, the welded connection also requires an open construction space, professional welding technology and equipment, and high skills requirements for construction personnel.

[0004] However, in actual projects, there are often some special cases. For example, when it is necessary to make a connection inside the existing pipeline, due to the limited internal space of the pipeline, both flange connection and variable diameter elbow welding are greatly restricted. Similarly, when the external environment does not have a construction work surface, such as in a narrow space or a hard-to-reach area, the traditional external pipe connection method is no longer applicable. How to achieve a stable connection of variable diameter steel pipes under limited construction work surface conditions has become a technical problem that needs to be solved in current pipeline engineering. Summary of the invention

[0005] In view of the problems existing in the prior art, the present invention provides a method for rigidly connecting nodes of variable diameter steel pipes in a confined space, aiming to provide a practical design and construction method for realizing rigid connection of variable diameter steel pipes in a confined space to meet engineering needs.

[0006] The present invention is achieved in this way.

[0007] A method for rigidly connecting nodes of variable diameter steel pipes in a confined space, comprising the following steps:

[0008] S1. Place one end of the large diameter steel pipe to be connected in a confined space;

[0009] S2. Insert the small diameter steel pipe from the other side of the confined space, insert the small diameter steel pipe into the large diameter steel pipe for a certain length, and use a positioning member to adjust the small diameter steel pipe so that the axis of the small diameter steel pipe is consistent with that of the large diameter steel pipe;

[0010] S3. Use 3D scanning to measure the relative positions, specifications and dimensions of large-diameter steel pipes and small-diameter steel pipes in detail and import them into the computer to build a model; use finite element analysis software to perform force analysis to determine the specifications, dimensions and quantity of the annular stiffeners, sealing annular plates and guide plates;

[0011] S4. According to the analysis results, the annular stiffening plate, the sealing annular plate and the guide plate are cut and processed by a CNC machine tool;

[0012] S5. The annular stiffening plate is arranged in the gap between the inner wall of the large-diameter steel pipe and the outer wall of the small-diameter steel pipe, and is positioned and welded. The welding quality is tested and accepted. After the acceptance is qualified, the annular stiffening plate and the surrounding pipelines are sprayed with anti-corrosion paint;

[0013] S6. After positioning and welding, the sealing annular plate will seal the gap between the inner wall of the large-diameter steel pipe and the outer wall of the small-diameter steel pipe. The welding quality will be inspected and accepted. After passing the acceptance, the sealing annular plate and the surrounding pipelines will be sprayed with anti-corrosion paint;

[0014] S7. The guide plate with a guide function connects one end of the small diameter steel pipe located inside the large diameter steel pipe and the inner wall of the large diameter steel pipe. After positioning and welding, the welding quality is inspected and accepted. After passing the acceptance, the guide plate and the surrounding pipelines are sprayed with anti-corrosion paint;

[0015] S8. Blow the filling material to ensure that the filling material is densely filled in the gap between the confined space and the large-diameter steel pipe and the small-diameter steel pipe;

[0016] S9. Inspection and acceptance.

[0017] As a preferred technical solution, there are multiple annular stiffening plates, which are evenly arranged in the radial direction in the gap between the inner wall of the large-diameter steel pipe and the outer wall of the small-diameter steel pipe, and are connected by fillet welds.

[0018] As a preferred technical solution, the sealing annular plate is circumferentially arranged between adjacent annular stiffening plates close to one end of the large-diameter steel pipe, and is connected by split-cut full-penetration welding.

[0019] As a preferred technical solution, the number of the sealing annular plates is the same as the number of the annular stiffening plates.

[0020] As an optimal technical solution, the guide plate is trumpet-shaped, and the side with a larger opening of the guide plate is welded to the inner wall of the large-diameter steel pipe, and the side with a smaller opening is welded to one end of the small-diameter steel pipe where an annular stiffening plate is provided, and the welding method is split-cut full-penetration welding.

[0021] As a preferred technical solution, the guide plate is composed of 2N guide plate monomers, where N is a natural number greater than 0.

[0022] As a preferred technical solution, the welds between adjacent guide plates are staggered with the welds between adjacent sealing annular plates.

[0023] As a preferred technical solution, the annular stiffening plate, the sealing annular plate, the guide plate, the large-diameter steel pipe and the small-diameter steel pipe are made of the same material.

[0024] As a preferred technical solution, the annular stiffening plate, sealing annular plate and guide plate are numbered after processing.

[0025] The advantages and technical effects of the present invention are as follows:

[0026] The present invention provides a method for rigidly connecting nodes of variable-diameter steel pipes in a confined space. According to the existing specifications, dimensions, relative offset positions and other conditions of large and small diameter steel pipes, 3D scanning and CNC cutting can be used to cut materials in advance in the factory and assemble and install them on site, thereby connecting steel pipes of two diameters and forming a reliable rigid connection node. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is an overall schematic diagram of a rigid connection node of a variable diameter steel pipe in a confined space for implementing the present invention;

[0028] Figure 2 for Figure 1 Right view of;

[0029] Figure 3 It is a structural schematic diagram when completing step S1;

[0030] Figure 4 This is a schematic diagram of the structure when step S2 is completed;

[0031] Figure 5 for Figure 4 Right view of;

[0032] Figure 6 It is a structural schematic diagram when completing step S5;

[0033] Figure 7 for Figure 6 Right view of;

[0034] Figure 8 for Figure 7 A magnified view of the part A in the middle;

[0035] Fig. 9 This is a schematic diagram of the structure when step S6 is completed;

[0036] Fig.10 for Fig. 9 A magnified view of the part B in the middle;

[0037] Fig.11 for Fig.10 Right view of;

[0038] Fig.12 It is a structural schematic diagram when completing step S7;

[0039] Fig.13 for Fig.12 A magnified view of the local C in the middle;

[0040] Fig.14 for Fig.13 Left view of .

[0041] In the figure: 1. Existing concrete pipe; 2. Large diameter steel pipe; 3. Small diameter steel pipe; 4. Annular stiffening plate; 5. Sealing annular plate; 6. Guide plate; 7. Filling material. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0043] like Figures 1 to 14 As shown, the present invention discloses a method for rigidly connecting nodes of variable diameter steel pipes in a confined space, and the steps are as follows:

[0044] S1. Place one end of the large diameter steel pipe 2 to be connected in the existing concrete pipe 1 or other confined space;

[0045] S2, insert the small diameter steel pipe 3 from the other side of the existing concrete pipe 1, insert the small diameter steel pipe 3 into the large diameter steel pipe 2 for a certain length, and use the positioning member to adjust the small diameter steel pipe 3 so that the axis of the small diameter steel pipe 3 is consistent with that of the large diameter steel pipe 2;

[0046] S3. Use 3D scanning to measure the relative position and specifications of the large diameter steel pipe 2 and the small diameter steel pipe 3 in detail and import them into the computer to establish a model; use finite element analysis software to perform force analysis to determine the specifications, dimensions and quantity of the annular stiffener 4, the sealing annular plate 5 and the guide plate 6;

[0047] S4, according to the analysis results, the annular stiffening plate 4, the sealing annular plate 5 and the guide plate 6 are cut and processed by a CNC machine tool;

[0048] S5, the annular stiffening plate 4 is arranged in the gap between the inner wall of the large diameter steel pipe 2 and the outer wall of the small diameter steel pipe 3, and the positioning and welding are performed, and the welding quality is tested and accepted. After the acceptance is qualified, the annular stiffening plate 4 and the surrounding pipelines are sprayed with anti-corrosion;

[0049] S6. After the sealing annular plate 5 is positioned and welded, the gap between the inner wall of the large-diameter steel pipe 2 and the outer wall of the small-diameter steel pipe 3 is sealed, and the welding quality is inspected and accepted. After the acceptance is qualified, the sealing annular plate 5 and the surrounding pipelines are sprayed with anti-corrosion paint;

[0050] S7, the guide plate 6 with a guide function connects one end of the small diameter steel pipe 3 located inside the large diameter steel pipe 2 and the inner wall of the large diameter steel pipe 2, and after positioning and welding, the welding quality is inspected and accepted. After passing the acceptance, the guide plate 6 and the surrounding pipelines are sprayed with anti-corrosion paint;

[0051] S8, blowing filling material 7, to ensure that the filling material 7 is densely filled in the limited space and the gap between the large diameter steel pipe 2 and the small diameter steel pipe 3;

[0052] S9. Inspection and acceptance.

[0053] like Figure 3 As shown, the confined space in step S1 includes but is not limited to the existing concrete pipe 1. This embodiment takes the existing concrete pipe 1 as an example. The large-diameter steel pipe 2 penetrates into the existing concrete pipe 1 for a distance, and a space for the installation of the small-diameter steel pipe 3 is reserved. The outer wall of the large-diameter steel pipe 2 does not contact the inner wall of the existing concrete pipe 1, and a space is reserved for the filling of the filling material 7 in the final stage.

[0054] like Figures 4-5 As shown, to ensure that the connection between the large diameter steel pipe 2 and the small diameter steel pipe 3 meets the design and construction requirements, the ends of the large diameter steel pipe 2 and the small diameter steel pipe 3 to be connected need to overlap by a certain length to facilitate the installation of each connecting component.

[0055] During the construction process, laser positioning is used to ensure that the axes of the large diameter steel pipe 2 and the small diameter steel pipe 3 are consistent. When the axes of the large diameter steel pipe 2 and the small diameter steel pipe 3 are consistent, the gap between the outer wall of the small diameter steel pipe 3 and the inner wall of the large diameter steel pipe 2 is a circular gap, and the size of each connecting component installed in the gap is consistent, which is convenient for the staff to carry out construction. If the axis deviates, the gap between the outer wall of the small diameter steel pipe 3 and the inner wall of the large diameter steel pipe 2 is non-circular, and the sizes of the connecting components are different, which increases the construction difficulty of the staff and affects the work efficiency.

[0056] The positioning component includes but is not limited to a jack, and the small diameter steel pipe 3 is adjusted by the jack to make the axes of the large diameter steel pipe 2 and the small diameter steel pipe 3 consistent; after the adjustment is completed, it is replaced with an annular stiffening plate 4 for subsequent positioning and welding.

[0057] Compared with manual measurement, the 3D scanning in step S3 is more convenient, faster and more accurate, thus improving work efficiency.

[0058] The finite element analysis software, such as ANSYS and ABAQUS, can perform stress analysis on complex connection nodes and quickly obtain the required specifications, dimensions and quantity of the annular stiffening plate 4, the sealing annular plate 5 and the guide plate 6.

[0059] The CNC machine tool in step S4 can accurately manufacture the annular stiffener 4, the sealing annular plate 5 and the guide plate 6 according to the analysis results for subsequent installation. When the axes of the large-diameter steel pipe 2 and the small-diameter steel pipe 3 are inconsistent, resulting in uneven sizes of the annular stiffener 4, the sealing annular plate 5 and the guide plate 6, the CNC machine tool can still accurately manufacture the required components to avoid affecting the construction progress due to size deviation.

[0060] After the annular stiffening plate 4, the sealing annular plate 5 and the guide plate 6 are processed, each component is numbered, and different installation positions correspond to different numbers, so that the staff can find the corresponding components more conveniently and quickly during construction, thereby improving work efficiency; and preventing the measurement deviation from causing inconsistent sizes of the components, in the absence of numbers, the staff cannot quickly find the corresponding components, thereby increasing the difficulty of construction.

[0061] like Figures 6 to 8 As shown, there are multiple annular stiffening plates 4, which are evenly arranged in the radial direction in the gap between the inner wall of the large diameter steel pipe 2 and the outer wall of the small diameter steel pipe 3, and play the role of fixing the position of the large diameter steel pipe 2 and the small diameter steel pipe 3; at the same time, the force is increased to make the pipeline connection more stable.

[0062] Preferably, the diameter difference between the large diameter steel pipe 2 and the small diameter steel pipe 3 is 150-200 mm, and the thickness of the annular stiffening plate 4 is 8-10 mm. When the diameter difference between the large diameter steel pipe 2 and the small diameter steel pipe 3 is large, the distance between the two pipe walls becomes larger, and the thickness of the annular stiffening plate 4 will increase accordingly according to the stress conditions.

[0063] Preferably, the number of the annular stiffening plates 4 is 16; the staff arranges an annular stiffening plate 4 every 500 mm according to the length of the circumference of the small diameter steel pipe 3 to meet the force requirements. The larger the diameter of the connected pipe, the more annular stiffening plates 4 are required according to the force analysis.

[0064] Preferably, the annular stiffening plate 4 is connected to the pipe walls of the large-diameter steel pipe 2 and the small-diameter steel pipe 3 by using fillet welds.

[0065] Further preferably, the material of the annular stiffening plate 4 is the same as that of the large-diameter steel pipe 2 and the small-diameter steel pipe 3, so as to ensure that the connection strength of the pipes is the same and does not affect subsequent use.

[0066] like Figures 9-11As shown, the sealing annular plate 5 is circumferentially welded between adjacent annular stiffening plates 4 close to one end of the large-diameter steel pipe 2 to play a role in space closure.

[0067] Preferably, the number of the sealing annular plates 5 is the same as the number of the annular stiffening plates 4 , to ensure that the sealing annular plates 5 seal the gap between the inner wall of the large-diameter steel pipe 2 and the outer wall of the small-diameter steel pipe 3 .

[0068] Preferably, the sealing annular plate 5 is welded to the walls of the large-diameter steel pipe 2 and the small-diameter steel pipe 3 by split-cut full-penetration welding; the welded sealing annular plate 5 plays a role in supporting the large-diameter steel pipe 2 and the small-diameter steel pipe 3.

[0069] Further preferably, the material of the sealing annular plate 5 is the same as that of the large-diameter steel pipe 2 and the small-diameter steel pipe 3, ensuring that the overall strength of the sealing annular plate 5 and the pipe remains unchanged after welding, avoiding damage to the connection parts due to inconsistent strength during use, thereby increasing maintenance costs.

[0070] like Figures 12-14 As shown, the guide plate 6 is trumpet-shaped and plays a role in guiding water flow, which is convenient for water flow to pass through. The side with a large opening of the guide plate 6 is welded to the inner wall of the large-diameter steel pipe 2, and the side with a small opening is welded to one end of the small-diameter steel pipe 3 where the annular stiffening plate 4 is provided; the guide plate 6 is welded with the small-diameter steel pipe 3 and the large-diameter steel pipe 2 by split-cut full-penetration welding. In order to ensure the guiding effect, adjacent guide plates 6 need to be welded and fixed to avoid leaving gaps to cause water penetration.

[0071] Preferably, the horizontal angle between the guide plate 6 and the inner wall of the large diameter steel pipe 2 is 30°, which is conducive to the circulation of water. If the diameter difference between the large diameter steel pipe 2 and the small diameter steel pipe 3 is large, the horizontal angle between the guide plate 6 and the inner wall of the large diameter steel pipe 2 will also change according to the construction requirements.

[0072] Preferably, the guide plate 6 is composed of a plurality of guide plate monomers. The integrally formed guide plate 6 manufactured by a CNC machine tool cannot be directly installed as a whole into the pipe to be connected, and needs to be cut first to facilitate the staff to weld the guide plate 6 into the pipe.

[0073] Further preferably, the number of the guide plate units is 2N, where N is a natural number greater than 0; an even number of guide plate units can be installed symmetrically, thereby improving the overall stability; the welds between adjacent guide plate units and the welds between adjacent sealing annular plates 5 are staggered, thereby improving the overall strength and avoiding damage to the welds due to the impact of water flow.

[0074] The material of the guide plate 6 is the same as that of the large-diameter steel pipe 2 and the small-diameter steel pipe 3, ensuring that the strength of the guide plate 6 and the pipe after welding remains consistent, thereby increasing the service life and reducing pipeline maintenance.

[0075] In the confined space of the construction site, generally only one end is close to the pipe interface, which is convenient for manual operation. The filling material 7 is blown in from one side of the existing concrete pipe 1 to avoid vibration of the pipe when water is passed, which affects the service life of the pipe.

[0076] The filling material 7 can be selected from suitable materials according to construction requirements, such as concrete and mortar.

[0077] After completing all operations, the final product is inspected according to the specification requirements.

[0078] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for rigidly connecting nodes of variable diameter steel pipes in a confined space, characterized in that: The following steps are involved: S1. placing one end of the large diameter steel pipe (2) to be connected in a confined space; S2, inserting the small diameter steel pipe (3) from the other side of the confined space, the small diameter steel pipe (3) is inserted into the large diameter steel pipe (2) for a certain length, and adjusting the small diameter steel pipe (3) by using a positioning member so that the axis of the small diameter steel pipe (3) is consistent with that of the large diameter steel pipe (2); S3, using 3D scanning to measure the relative position and specifications of the large diameter steel pipe (2) and the small diameter steel pipe (3) in detail and import them into a computer to establish a model; using finite element analysis software to perform a force analysis to determine the specifications, dimensions and quantity of the annular stiffening plate (4), the sealing annular plate (5) and the guide plate (6); S4. According to the analysis results, the annular stiffening plate (4), the sealing annular plate (5) and the guide plate (6) are cut and processed by a CNC machine tool; S5, placing the annular stiffening plate (4) in the gap between the inner wall of the large diameter steel pipe (2) and the outer wall of the small diameter steel pipe (3), positioning and welding, and inspecting and accepting the welding quality. After passing the acceptance, anti-corrosion spraying is performed on the annular stiffening plate (4) and the surrounding pipelines; S6. After positioning and welding, the sealing annular plate (5) will seal the gap between the inner wall of the large diameter steel pipe (2) and the outer wall of the small diameter steel pipe (3). The welding quality is inspected and accepted. After passing the acceptance, the sealing annular plate (5) and the surrounding pipelines are sprayed with anti-corrosion paint; S7, connecting one end of the small diameter steel pipe (3) located inside the large diameter steel pipe (2) with a guide plate (6) having a guide function to the inner wall of the large diameter steel pipe (2), positioning and welding, and then inspecting and accepting the welding quality. After passing the acceptance, anti-corrosion spraying is performed on the guide plate (6) and the surrounding pipelines; S8, blowing the filling material (7) to ensure that the filling material (7) is densely filled in the confined space and the gap between the large-diameter steel pipe (2) and the small-diameter steel pipe (3); S9. Inspection and acceptance.

2. The method for rigidly connecting nodes of variable diameter steel pipes in a confined space as claimed in claim 1, characterized in that: The annular stiffening plates (4) are multiple in number and are evenly arranged in a radial direction in the gap between the inner wall of the large diameter steel pipe (2) and the outer wall of the small diameter steel pipe (3), and are connected by fillet welds.

3. The method for rigidly connecting nodes of variable diameter steel pipes in a confined space as claimed in claim 1, characterized in that: The sealing annular plate (5) is circumferentially arranged between adjacent annular stiffening plates (4) close to one end of the large-diameter steel pipe (2), and is connected by split-cut full-penetration welding.

4. The method for rigidly connecting nodes of variable diameter steel pipes in a confined space as claimed in claim 3, characterized in that: The number of the sealing annular plates (5) is the same as the number of the annular stiffening plates (4).

5. The method for rigidly connecting nodes of variable diameter steel pipes in a confined space as claimed in claim 1, characterized in that: The guide plate (6) is trumpet-shaped, and the side with a larger opening of the guide plate (6) is welded to the inner wall of the large-diameter steel pipe (2), and the side with a smaller opening is welded to one end of the small-diameter steel pipe (3) provided with an annular stiffening plate (4), and the welding method adopts split-cut full-penetration welding.

6. The method for rigidly connecting nodes of variable diameter steel pipes in a confined space as claimed in claim 5, characterized in that: The guide plate (6) is composed of 2N guide plate monomers, where N is a natural number greater than 0.

7. The method for rigidly connecting nodes of variable diameter steel pipes in a confined space as claimed in claim 6, characterized in that: The welds between adjacent guide plates (6) and the welds between adjacent sealing annular plates (5) are staggered.

8. The method for rigidly connecting nodes of variable diameter steel pipes in a confined space as claimed in claim 7, characterized in that: The horizontal angle between the guide plate (6) and the inner wall of the large-diameter steel pipe (2) is 30°.

9. The method for rigidly connecting nodes of variable diameter steel pipes in a confined space as claimed in claim 1, characterized in that: The annular stiffening plate (4), the sealing annular plate (5), the guide plate (6), the large-diameter steel pipe (2) and the small-diameter steel pipe (3) are made of the same material.

10. The method for rigidly connecting nodes of variable diameter steel pipes in a confined space as claimed in claim 1, characterized in that: After processing, the annular stiffening plate (4), the sealing annular plate (5) and the guide plate (6) are numbered.

Images