Method of preparing ends of pipes with inner polymer coating for welding

FIELD: welding jobs.

SUBSTANCE: invention relates to the methods of preparing the ends of pipes with inner polymer coating for welding, and can be used in repair of pipelines. The proposed method consists in the following. A tip with a rubber seal ring is fitted into the pipe with inner polymer coat, the aforesaid seal ring being place on pre-compressed smaller-diameter tip part, some 150 to 200 mm-long. Then using a mandrel, the aforesaid smaller-diameter part is expanded for the pipes ends sizes and shapes to match.

EFFECT: sealing of welded pipes, simpler procedure.

1 dwg

 

The invention relates to the field of pipeline transport and can be used in the repair of pipelines with internal polymer coating for welding.

It is known that when welding two pipes end-to-end produce preparatory work to edit them all. Edit ends of the pipes necessary to ensure that matches the size and shape of pipe ends if the ends are dents, deviations from the circular shape of the pipe and the diameter from the nominal value.

There is a method of preparation of pipe ends by deformation of the outer centralizer and other devices of the edges of the connected pipe ends (see guidance document. Statement on the elimination of accidents and damage to oil pipelines RD-39-110-91. Rotaprint PI-TER-1992).

The closest technical solution is welded connection of pipes with internal coating and a method of connecting pipes with internal coating (see patent 2140038), namely, that the inner surface of the pipe ends in place surfacing is made in the form of a bell, and the ends of the deposited layers have an annular groove, followed by the cutting edges of the pipe, and before applying a corrosion-resistant alloy inner surface of the pipe end is subjected to processing under the bell, and when the cutting edges for welding to produce an annular groove, blending into the end naplavlennogo the layer, and welding end sections are overlapping seam in two stages, first fill the root seam homogeneous weld electrode layer, and then filling the seam.

The disadvantage is the occurrence of high stresses in the deformation of the metal pipe at the edges of the distributed application efforts and the complexity of the execution of the method.

The purpose of the invention is improving the efficiency of the method by the features of the software matches the size and shape of pipe ends and simplification of the method.

This objective is achieved in that the inner cavity of the pipe with a polymer coating insert the tip with a rubber o-ring located on the pre-reduced in diameter portion of the tip length of 150-200 mm, and then using a mandrel carrying out radiatia reduced diameter portion of the tip to ensure coincidence of the size and shape of the welded pipe ends.

The drawing shows a General view of the device for implementing the method.

The device includes steel pipe 1, tip 2, a rubber o-ring 3 and the inner polymer coating 4.

The method is implemented as follows.

Into the internal cavity of the steel pipe 1 with a polymer coating 4 insert the tip 2 with sealing ring 3 and open it using a mandrel, osushestvlyaem the preparation of connected pipes for welding.

The use of the present invention will allow for the preparation of the ends of steel pipes with polymeric coating, providing match the size and shape of the welded pipe ends.

The method of preparation of the pipe ends with an inner polymer coating for welding, which consists in the fact that the inner cavity of the pipe with a polymer coating insert the tip with a rubber o-ring located on the pre-reduced in diameter portion of the tip length of 150-200 mm, and then using a mandrel carrying out radiatia reduced diameter portion of the tip to ensure coincidence of the size and shape of the welded pipe ends.



 

Same patents:

FIELD: technological processes; pipes.

SUBSTANCE: dimensions and shapes of joined pipe ends are compared, distributed straightening force direction and intensity is defined, pipe ends dimensions and shapes are matched by application of distributed straightening force to pipe walls along its whole diameter. At that distributed straightening force is applied to pipe generatrix in section, length of which is established depending on intensity of distributed straightening force. In part of section that starts from pipe end, intensity of distributed force is established with constant value, and in remaining part it is evenly reduced down to zero.

EFFECT: reduction of wall surface curvature and lower stress in it.

2 dwg

FIELD: technological processes.

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EFFECT: improved quality of weld seams in overlapping joints of steel pipes, reduced hopping during rotation of long-length welded article, reduced cost of welded product.

3 cl, 3 dwg, 1 tbl

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FIELD: mechanical engineering; argon-arc welding.

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2 tbl

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4 dwg

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EFFECT: improved quality of welded seams.

8 dwg

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2 cl, 1 dwg

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