RU2288826C1 - Method for preparing tube butts to welding - Google Patents

Abstract

FIELD: building, repairing main pipelines for transporting liquids and gases, namely restoration of such pipelines by changing defective portion.

SUBSTANCE: method comprises steps of marking out and trimming ends of repairing "reel" and tube ends for providing coincidence of their edges; marking out tube end portions according to ends of false tube having telescopically changed length. Initially false tube in compressed state is mounted between tube ends and then it is put onto tubes without gap between inner surface of false tube and outer surfaces of tube end portions. Length of repairing "reel" is determined according to length of false tube after mounting the last on end portions of tubes.

EFFECT: enhanced accuracy of marking out tube butts and repairing reel, simplified marking out process, lowered labor consumption of marking out and mounting operations.

1 dwg

Description

The invention relates to the field of construction and repair of pipelines for transporting liquids and gases, and is intended for the repair of pipelines with the replacement of a defective area.

A known method of marking pipe joints using a device that secures the pipe before cutting the defective area, marking, mounting and centering the "repair" coil / 1 /. Clamps are mounted at the ends of the removed section of the pipeline. Stringers are threaded through the holes in the tides of one of the clamps, on which the movable stops are successively mounted, stringers are threaded into the tide holes of the second clamp. After cutting and removing the defective area, marking, installation and centering of the new "coil" is carried out.

The disadvantages of this method are the complexity of the design of the device used, the high complexity of fixing the pipeline and the inaccuracy of the marking of the joints of pipes and repair "coil". The latter is due to the fact that the marking is done "by eye" without the use of any marking devices or devices.

A device-support for maintaining the pipeline / 2 /. It contains a base with racks, balancing levers with bushings placed on racks movably with height adjustment. A suspension with rollers that support the pipeline is pivotally mounted on the balancing levers. The device is designed to fix the pipeline and eliminate misalignment when cutting a defective area. The described invention has the same disadvantages as mentioned above.

The closest in technical essence to the claimed invention is a method of preparing the ends of the pipes for welding when replacing a defective section of the main pipeline / 3 /. The method consists in marking and trimming the repair "coil" and the ends of the pipes, ensuring that their edges coincide. In this case, the comparison of the sizes and shapes of the connected pipe ends is carried out with a standard circle whose diameter is equal to the nominal diameter of the pipeline being repaired. Ensuring the coincidence of the sizes and shapes of the ends of the pipes is carried out before mounting the “coil” by plastic deformation of the metal of the pipes due to the distributed force on the ends of the pipes. This operation allows you to ensure the same diameter of the circumference of the ends of the pipes and repair "coil".

The prototype device / 4 / contains the outer and inner pipes (nozzles) telescopically and movably connected to each other.

The disadvantages of the method and device taken as a prototype are: the high complexity of the plastic deformation of the ends of the pipes and the need to use special equipment; the difficulty of ensuring accurate marking of the joints of the pipes and the repair "coil" and the coincidence of their edges in the plane of the slices, since no measures and marking devices are provided for this. The known prototype device cannot be used as a marking device, since its design does not include dimensional ratios of the inner diameter of the nozzles to the outer diameter of the pipeline, allowing it to be used as a false pipe repair “coil”.

The present invention is aimed at improving the accuracy of the marking of the joints of pipes and repair "coil", simplifying the marking process and reducing the complexity of marking and installation work.

The problem is solved in that in the method of preparing pipe joints for welding, the ends of the pipes are marked at the ends of the raised pipe with a variable length worn on the ends of the pipes, and the length of the repair coil is determined by the length of the said raised pipe after it is mounted at the ends of the pipes, while the ends of the repair "coil" are cut off in planes perpendicular to its axis.

In an apparatus for the preparation of pipe joints for welding, comprising a dummy tube, consisting of outer and inner pipes telescopically and adjustably connected to each other, the inner diameter d _ext dummy pipe equal to the outer diameter d _n conduit with an allowance + (0,002 ... 0.003) d _n

A method of preparing pipe joints for welding and a device for its implementation are illustrated by drawings. The drawing shows a layout diagram of a defective section of the pipeline in front view and top view. On remote elements in an enlarged image shows the joints of the raised pipe and the pipeline being repaired, the device of the raised pipe.

A device that implements a method for preparing pipe joints for welding is a false pipe 1, consisting of external and internal pipes 2 and 3, telescopically and movably connected to each other. The telescopic joint has been machined with minimal roughness in order to ensure an accurate and flexible connection of the nozzles. The ends of the raised pipe are machined in planes strictly perpendicular to its axis.

The inner diameter d _ext dummy pipe equal to the outer diameter d _n repaired pipeline with an allowance + (0,002 ... 0,003) d _n. This is necessary so that the false pipe has the ability to be worn on the ends of the pipes 4 and 5 of the pipeline being repaired when they are misaligned. To facilitate the installation of the raised pipe, there are handles 6.

A method of preparing pipe joints for welding is as follows.

In preparation for the repair work, a false pipe is made.

When carrying out repairs, the defective section of the pipeline being repaired is first cut out. After cutting the defective section, the ends of the pipes 4, 5 due to internal stresses, shrinkage of the soil and other reasons, change their initial position and are displaced relative to each other. In the general case, the ends of the pipes are two intersecting straight lines located in different planes at an angle to each other.

Next, in the cut section of the pipeline, the false pipe 1 is inserted in a compressed form. Then, using the handles 6 tubes 2, 3 dummy pipe diluted in hand and pull on the ends of the pipes 4 and 5. The clearance between the inner diameter d _ext dummy tube and the outer diameter d _n pipeline provides the dummy tube set on the tube ends when they misalignment. It is recommended that the approach depth be kept to the minimum limits that ensure that there are no gaps between the ends of the raised pipe and the ends of the pipes.

After installing a false pipe at the ends of the pipes with chalk or scribble along the ends of the false pipe on the surfaces of the pipes 4, 5 mark their cutting lines. At the same time, the length of the raised pipe in the installed state is measured. Then the false pipe is dismantled.

According to the measured length of the raised pipe, a repair coil is made. The ends of the repair "coil" are cut off in planes perpendicular to its axis. The ends of the pipes 4, 5 are cut along the marked cutting lines, cut the edges and prepare for welding.

After the described operations, the “coil” is mounted in the pipeline, the joints are finally adjusted and the whole structure is welded.

The allowance + (0.002 ... 0.003) d _n given in the application materials is optimal and sufficient for the installation of a raised pipe with a misalignment of pipes 4, 5. With an allowance of less than 0.002 d _n, putting a raised pipe on the ends of the pipes will be difficult or impossible if the misalignment of the pipes exceeds 5-10 mm, and the angles between the axes of the pipes are more than 3-5 degrees. With an allowance of more than 0.003d _n , gaps are formed between the inner surface of the raised pipe and the outer surface of the pipe ends, which will lead to inaccurate marking and trimming of the pipes.

The present invention provides accurate marking of the joints of pipes and repair "coil" with high performance marking and installation work.

Compared with the prototype invention, the invention has the following advantages:

1. The prototype invention has a marking accuracy of ± 3-5 mm, since it does not provide any marking measures and marking devices. The present invention provides a marking accuracy of ± 1-2 mm due to the fact that the marking of the pipe joints is carried out at the ends of the false pipe, a copy of which is a repair "coil" along the length.

2. The present invention provides a simplification of the marking process, as a result of which the productivity of marking operations is increased by 2-3 times. This is achieved through simple marking of pipe joints along the ends of the raised pipe.

3. The present invention does not require bulky equipment for additional processing of pipe ends, which reduces the cost of repair work 1.5-2 times.

4. Marking work according to the invention consists of simple operations, which reduces the complexity of repair work by 20-30%.

The present invention can be used in the repair work on pipelines transporting gaseous and liquid products.

INFORMATION SOURCES

1. RF patent №2217650, M. cl. F 16 L 1/036. Device for centering pipes.

2. RF patent No. 2079761, M. cl. F 16 L. Support device for supporting the pipeline.

3. RF patent №2123922, M. cl. B 23 P 6/00; B 23K 33/00. A method of preparing pipe ends for welding when replacing a defective section of a trunk pipeline.

4. Application for invention No. 94004600, M. cl. F 16V 7/10. Telescopic connection.

Claims (1)

A method of preparing pipe joints for welding when replacing a defective section of the main pipeline, including marking and trimming the repair "coil" and pipe ends to ensure that their edges coincide, characterized in that the pipe ends are marked at the ends of the false pipe with a telescopically variable length that is initially mounted in a compressed form between the ends of the pipes, and then put on the pipes by diluting it to ensure that there are no gaps between the inner surface of the raised pipe and the outer surfaces of the ends of the pipes, this the length of the repair "coil" is determined by the length of the false pipe after its installation at the ends of the pipes.