A method of pipe replacement which cannot be welded on line

Abstract

The application discloses a pipeline replacement method incapable of on-line welding and belongs to the field of chemical machinery. The application provides a pipeline replacement method incapable of on-line welding in the pipeline replacement and installation process. The treatment method is to weld a plurality of vertically distributed nuts on the non-adhesion surface of a flange in advance, to use the multi-point positioning principle to lock the pipeline to be welded after threading, to effectively fix the flange and the pipeline to be welded, and to bring the possibility of off-line welding. The application discloses a pipeline replacement method incapable of on-line welding, and the pipeline off-line welding replacement condition is treated by using the application. The on-site operation environment can be greatly relieved, the production shutdown risk and the safety risk are reduced, and great operation safety guarantee and good operation conditions are brought to operation personnel.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of pipeline replacement, and particularly relates to a pipeline replacement method incapable of on-line welding. BACKGROUND

[0002] In the industrial production process, replacing or installing a pipeline is a common pipeline installation or repair condition. In this case, pipeline flange connection is a common pipeline connection means. Two flanges are tightly attached through screw fastening to realize sealing and ensure stable conveying of fluid and gas in the pipeline without leakage.

[0003] To ensure sealing connection, the two flanges to be connected must be consistent in angle to realize close attachment and achieve good sealing through fastening. Therefore, the welding angle of the flange is particularly crucial when the flange is welded to the pipeline. Especially when the two ends of the pipeline to be replaced are respectively connected to the flanges of the original fixed pipeline, the flanges at the two ends of the pipeline to be replaced respectively adapt to the angles of the flanges to be connected on the two sides.

[0004] In the industry, in order to ensure that the first flange to be installed and the second flange to be installed on the pipeline to be replaced or installed can respectively attach to the first flange to be connected and the second flange to be connected after welding, the commonly used method is to first prefabricate a suitable pipeline to be replaced or installed according to the length of the pipeline, and then live install the first flange to be installed and the second flange to be installed on the pipeline to be replaced or installed without welding. Then, after attaching the first flange to be installed to the first flange to be connected and the second flange to be installed to the second flange to be connected, the flanges are fastened with screws, and after pre-assembly, the first flange to be installed and the second flange to be installed are directly welded on site or spot-welded to fix the angle of the flanges, and then disassembled for off-line repair welding.

[0005] The above method is a commonly used method for replacing or installing pipeline flange welding, which requires fire construction at the maintenance site. However, the disadvantage is that in production, there are some maintenance sites that cannot realize on-site welding due to narrow space, too close to the structure, high altitude, inability to completely cut off the medium in the maintenance pipeline, or production prohibited fire area, etc. This method is not applicable. Only after pre-welding is completed, the connection and installation can be carried out. At this time, because the angle of the flange cannot be accurately predicted, one end of the flange may not be attached, which brings great trouble to the maintenance construction and easily causes flange leakage.

[0006] In the case of narrow repair area, close to the structure, high altitude, and the medium in the pipeline cannot be completely cut off, in order to replace the pipeline, it is often necessary to take measures such as expanding the repair area, removing the surrounding structure, welding personnel climbing operation, expanding the shutdown range, etc. In order to achieve the purpose of welding. Especially in the production of fireproof area, it is also necessary to stop production, purge the pipeline, and pass the inspection before welding. The above conditions will bring greater difficulty to the repair operation, delay the operation time, increase the risk coefficient of the welding operation personnel, and cannot meet the needs of the people.

[0007] Therefore, we propose a method for replacing the pipeline which cannot be welded online. SUMMARY

[0008] The purpose of the present application is to overcome the defects of the prior art and provide a method for replacing the pipeline which cannot be welded online.

[0009] To achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0010] A method for replacing the pipeline which cannot be welded online, comprising the following steps:

[0011] S1, prepare two groups of pipes to be replaced or installed in the middle of the to-be-connected flanges;

[0012] S2, vertically and uniformly weld a plurality of nuts on the non-adhering surface of the two groups of flanges to be installed, and the nuts face the center of the flanges;

[0013] S3, put the flanges in S2 on the two ends of the pipes to be replaced or installed;

[0014] S4, tightly fasten the two groups of flanges to be installed with the two groups of flanges to be connected;

[0015] S5, install screws on the vertically welded nuts on the flange surface and tighten them to death, so that the to-be-installed flanges are fixed at an angle with the pipes to be replaced or installed;

[0016] S6, remove the flanges connected at both ends in S4, and remove the pipes to be installed or replaced;

[0017] S7, move the pipes to be replaced or installed to an appropriate area, and perform point welding of the flanges and the pipes;

[0018] S8, remove the screws and vertically welded nuts, and perform overall welding of the pipes and the flanges;

[0019] S9, install the welded pipes.

[0020] Preferably, the first to-be-connected flange, the second to-be-connected flange, the first to-be-installed flange, the second to-be-installed flange, the first flange connecting screw, the second flange connecting screw, the first dead-end fixing screw, the second dead-end fixing screw, the third dead-end fixing screw and the fourth dead-end fixing screw are prepared in advance in the step S1, and the pipeline in the step S1 can be a straight pipe or a bent pipe.

[0021] Preferably, a plurality of groups of nuts are vertically welded on the non-adjoining surfaces of the first to-be-installed flange and the second to-be-installed flange in the step S2.

[0022] Preferably, the first to-be-installed flange and the second to-be-installed flange, on which the plurality of groups of nuts are welded, are respectively installed at the two ends of the pipeline in the step S3.

[0023] Preferably, the first to-be-installed flange is adhered to the first to-be-connected flange and is fastened by the first flange connecting screw and the second flange connecting screw, and the second to-be-installed flange is adhered to the second to-be-connected flange and is fastened by the first flange connecting screw and the second flange connecting screw in the step S4, and the first flange connecting screw and the second flange connecting screw are arranged diagonally.

[0024] Preferably, the first dead-end fixing screw, the second dead-end fixing screw, the third dead-end fixing screw and the fourth dead-end fixing screw are respectively installed on the first to-be-installed flange and the second to-be-installed flange in the step S5, and the first dead-end fixing screw, the second dead-end fixing screw, the third dead-end fixing screw and the fourth dead-end fixing screw are all adhered to the outer wall of the pipeline, and the pipeline is fixed by dead end.

[0025] Preferably, the first flange connecting screw and the second flange connecting screw in the step S4 are disassembled, and the first to-be-connected flange and the second to-be-connected flange are disassembled in the step S6.

[0026] Preferably, the pipeline, the first to-be-installed flange and the second to-be-installed flange in the step S6 are moved to a suitable environment, and the first to-be-installed flange, the second to-be-installed flange and the pipeline are spot-welded in the step S7.

[0027] Preferably, the first dead-end fixing screw, the second dead-end fixing screw, the third dead-end fixing screw and the fourth dead-end fixing screw are disassembled after welding and fixing, and the nuts that are vertically and uniformly welded are cut off, and then the first to-be-installed flange, the second to-be-installed flange and the pipeline are fully welded in the step S8.

[0028] Preferably, the pipeline after welding is installed or replaced in the step S9.

[0029] Compared with the prior art, the pipeline replacement method according to the present application has the following beneficial effects:

[0030] 1. The pipe replacement or installation method of the present application can solve the problems of pipe installation and replacement in narrow areas, areas with structures interfering, high-altitude areas, areas where the medium in the pipe cannot be completely cut off for maintenance, and areas where production is prohibited from being started.

[0031] 2. The pipe replacement or installation method of the present application can make the pipe replacement or installation successful at one time, reduce the leakage caused by the tightness of the flange and the frequent rework caused thereby, save the operation time, and improve the reliability of the operation.

[0032] 3. The pipe replacement or installation method of the present application improves the working environment of the operation personnel, improves the safety guarantee of the operation personnel and production, and especially reduces the shutdown risk and safety risk caused by pipe replacement or installation in the chemical production area. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 It is a general structure diagram of the pipe replacement method of the present application which cannot be welded online.

[0034] Figure 2 It is a commonly used replacement method diagram in the industry in the pipe replacement method of the present application which cannot be welded online.

[0035] Figure 3 It is a diagram of the flange not being completely attached in the pipe replacement method of the present application which cannot be welded online.

[0036] Figure 4 It is a vertical nut welding diagram in the pipe replacement method of the present application which cannot be welded online.

[0037] Figure 5 It is a diagram of the screw being screwed up and dead in the front direction in the pipe replacement method of the present application which cannot be welded online.

[0038] Figure 6 It is a diagram of the screw being screwed up and dead in the side direction in the pipe replacement method of the present application which cannot be welded online.

[0039] Figure 7 It is a spot welding diagram in the pipe replacement method of the present application which cannot be welded online.

[0040] Figure 8 It is a comprehensive welding diagram in the pipe replacement method of the present application which cannot be welded online.

[0041] In the figure: 1, pipeline; 2, first to be butt flange; 3, second to be butt flange; 4, first to be installed flange; 5, second to be installed flange; 6, first flange connecting screw; 7, second flange connecting screw; 8, first dead center fixing screw; 9, second dead center fixing screw; 10, third dead center fixing screw; 11, fourth dead center fixing screw; 12, nut. DETAILED DESCRIPTION

[0042] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application. In addition, for the convenience of description, the "up", "down", "left", "right" and the like in the following are consistent with the up, down, left and right of the drawings, and the "first", "second" and the like in the following are for distinguishing description, and have no other special meanings.

[0043] In order to make the technical means, creative features, purposes and effects achieved by the present application easy to understand, the present application will be further described below with reference to the specific embodiments. Embodiment 1

[0044] Referring to Figures 1-8 Fig. 1 shows a pipeline replacement method that cannot be welded online, comprising the following steps:

[0045] S1, prepare two groups of pipelines 1 to be replaced or installed in the middle of the to-be-butted flanges;

[0046] Prepare the first to-be-butted flange 2, the second to-be-butted flange 3, the first to-be-installed flange 4, the second to-be-installed flange 5, the first flange connecting screw 6, the second flange connecting screw 7, the first dead center fixing screw 8, the second dead center fixing screw 9, the third dead center fixing screw 10 and the fourth dead center fixing screw 11 in advance. The pipeline 1 in step S1 can be a straight pipe or a bent pipe.

[0047] S2, vertically and uniformly weld a plurality of nuts 12 on the non-adhering surfaces of the two groups of to-be-installed flanges, and the nuts face the center of the flanges;

[0048] Vertically weld a plurality of nuts 12 on the non-adhering surfaces of the first to-be-installed flange 4 and the second to-be-installed flange 5.

[0049] S3, fit the flanges in S2 on both ends of the pipeline 1 to be replaced or installed;

[0050] Install the first to-be-installed flange 4 and the second to-be-installed flange 5, which are welded with a plurality of nuts 12, on both ends of the pipeline 1.

[0051] S4, respectively, with two ends of the flange to be connected to the flange to be installed;

[0052] The first to be installed flange 4 and the first to be connected flange 2 are attached and fastened by the first flange connecting screw 6 and the second flange connecting screw 7, and the second to be installed flange 5 and the second to be connected flange 3 are attached and fastened by the first flange connecting screw 6 and the second flange connecting screw 7, and the first flange connecting screw 6 and the second flange connecting screw 7 are diagonally arranged.

[0053] S5, install the screw on the vertically welded nut 12 on the flange surface and tighten it to death, so that the to-be-installed flange is angle-fixed with the to-be-replaced or installed pipeline 1;

[0054] First to death fixed screw 8, second to death fixed screw 9, third to death fixed screw 10 and fourth to death fixed screw 11 are respectively installed on the first to be installed flange 4 and the second to be installed flange 5, and the first to death fixed screw 8, the second to death fixed screw 9, the third to death fixed screw 10 and the fourth to death fixed screw 11 are all attached to the outer wall of the pipeline 1, and the pipeline 1 is fixed to death.

[0055] S6, remove the flanges connected at both ends in S4, and remove the to-be-installed or replaced pipeline 1;

[0056] The first flange connecting screw 6 and the second flange connecting screw 7 in step S4 are disassembled, and the first to be connected flange 2 and the second to be connected flange 3 are disassembled.

[0057] S7, move the to-be-replaced or installed pipeline 1 to an appropriate area of the environment, and perform flange and pipeline 1 spot welding;

[0058] The pipeline 1, the first to be installed flange 4 and the second to be installed flange 5 in step S6 are moved to an appropriate environment, and the first to be installed flange 4, the second to be installed flange 5 and the pipeline 1 are spot welded.

[0059] S8, remove the screw and the vertically welded nut 12, and perform overall welding of the pipeline 1 and the flange;

[0060] After welding and fixing, the first to death fixed screw 8, the second to death fixed screw 9, the third to death fixed screw 10 and the fourth to death fixed screw 11 are removed, and the vertically and uniformly welded nut 12 is cut off, and then the first to be installed flange 4, the second to be installed flange 5 and the pipeline 1 are fully welded.

[0061] S9, install the welded pipeline 1.

[0062] The pipeline 1 after welding is installed or replaced.

[0063] The pipeline replacement or installation treated by the method can solve the problems of pipeline 1 installation and replacement in narrow areas, areas with structure interference, high-altitude areas, areas where the medium in the pipeline cannot be completely cut off for maintenance, and areas where production is prohibited from fire.

[0064] The pipeline replacement or installation treated by the method can make the pipeline 1 replacement or installation successful at one time, reduce the leakage caused by the close fitting of the flanges and the frequent rework caused thereby, save the operation time, and improve the reliability of the operation.

[0065] The pipeline replacement or installation treated by the method improves the working environment of the operators, improves the safety guarantee of the operators and production, and especially reduces the shutdown risk and safety risk caused by the pipeline replacement or installation in the chemical production area.

[0066] The above is a further detailed description of the present application in combination with specific preferred embodiments, and the specific implementation of the present application cannot be limited to these descriptions. For ordinary skilled persons in the technical field to which the present application belongs, a number of simple deductions or substitutions can be made without departing from the concept of the present application, and all of them should be regarded as falling within the protection scope of the present application.

Claims

1. A method for replacing pipes that cannot be welded online, characterized in that, Includes the following steps: S1. Prepare the pipe (1) that needs to be replaced between the two sets of flanges to be connected. S2. Weld multiple sets of nuts (12) vertically and evenly to the center of the flange on the non-fitting surfaces of the two sets of flanges to be installed. S3. Fit the flanges to be installed at both ends of the pipe (1) to be replaced in S2; S4. Secure the two sets of flanges to be installed to the flanges at both ends to be connected. S5. Install screws on the nuts (12) that are vertically welded on the flange face of the flange to be installed and tighten them to fix the angle between the flange to be installed and the pipe (1) to be replaced. S6. Remove the flanges that are connected at both ends in S4 and take off the pipe to be replaced (1). S7. Move the pipe (1) to be replaced to a suitable area and spot weld the flange to be installed to the pipe (1); S8. Remove the screws and vertically welded nuts (12) and perform full welding of the pipe (1) and the flange to be installed; S9. Install the welded pipes (1).

2. A method for replacing pipes that cannot be welded online as described in claim 1, characterized in that: In step S1, the first flange to be connected (2), the second flange to be connected (3), the first flange to be installed (4), the second flange to be installed (5), the first flange connecting screw (6), the second flange connecting screw (7), the first locking screw (8), the second locking screw (9), the third locking screw (10), and the fourth locking screw (11) are prepared in advance. The pipe (1) in step S1 is a straight pipe or a bend.

3. A method for replacing pipes that cannot be welded online, as described in claim 2, characterized in that: In step S2, multiple sets of nuts (12) are vertically welded on the non-fitting surfaces of the first flange to be installed (4) and the second flange to be installed (5).

4. A method for replacing pipes that cannot be welded online, as described in claim 3, characterized in that: In step S3, the first flange (4) and the second flange (5) with multiple sets of nuts (12) are respectively installed at both ends of the pipe (1).

5. A method for replacing a pipe that cannot be welded online, as described in claim 4, characterized in that: In step S4, the first flange to be installed (4) and the first flange to be docked (2) are attached together and fastened with the corresponding first flange connecting screw (6) and second flange connecting screw (7). The second flange to be installed (5) and the second flange to be docked (3) are attached together and fastened with the corresponding first flange connecting screw (6) and second flange connecting screw (7). The first flange connecting screw (6) and the second flange connecting screw (7) are set diagonally.

6. A method for replacing a pipe that cannot be welded online, as described in claim 5, characterized in that: In step S5, a first locking screw (8), a second locking screw (9), a third locking screw (10), and a fourth locking screw (11) are installed on the first flange (4) and the second flange (5) respectively, and the first locking screw (8), the second locking screw (9), the third locking screw (10), and the fourth locking screw (11) are all in contact with the outer wall of the pipe (1) to lock the pipe (1).

7. A method for replacing a pipe that cannot be welded online, as described in claim 6, characterized in that: In step S6, the first flange connecting screw (6) and the second flange connecting screw (7) from step S4 are removed, and the first flange to be connected (2) and the second flange to be connected (3) are disassembled.

8. A method for replacing a pipe that cannot be welded online, as described in claim 7, characterized in that: In step S7, the pipe (1), the first flange to be installed (4), and the second flange to be installed (5) from step S6 are moved to a suitable environmental area, and the first flange to be installed (4), the second flange to be installed (5), and the pipe (1) are spot welded and fixed.

9. A method for replacing a pipe that cannot be welded online, as described in claim 8, characterized in that: In step S8, after welding and fixing, the first top-fixing screw (8), the second top-fixing screw (9), the third top-fixing screw (10) and the fourth top-fixing screw (11) are removed, and the nuts (12) that are welded vertically and evenly are cut off. Then, the first flange to be installed (4), the second flange to be installed (5) and the pipe (1) are fully welded.

10. A method for replacing a pipe that cannot be welded online, as described in claim 8, characterized in that: In step S9, the pipe (1) after welding is completed is replaced.

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