The main stages of assembly of pipelines – the 2nd part
It is necessary to hold in the head that welding of welded pryamoshovny pipes has certain features, namely, seams of adjoining pipes should be shifted on the third part of length of a circle (40мм and least) or on 100мм (a diameter more pipes more 100мм). Flanges iron are welded so that the mirror of a flange was strictly perpendicular to a pipe axis that is reached by introduction of a special square.
The distance from a welded seam prior to the beginning of a curve of the pipeline should not surpass 100мм, except cases when branches iron кругл oizognuty or shtamposvarny are used. The 8th this case the joint can take place in concrete proximity to a curve.
4. Cleaning prikhvatok. Specifically before carrying out welding of a surface of prikhvatochny seams are smoothed out to shine. On them should not remain scale or slags. Their existence will lower quality of the second layer of a seam.
5. Welding of pipes. It would seem, process is simple and does not ask huge knowledge and abilities, nevertheless, actually to collect the elements which are precisely ought to the drawing, leaves occasionally. At most that leaves even at the most experienced mechanic – approximate compliance, so to speak assembly "approximately". In field criteria it is heavy to provide the highest quality of cleaning of surfaces and quite good pro-cooking. Here therefore for assembly of parts of pipelines on productions special camps are used.
Generally camps consist of special tables, beams, carriages, the rollers, directing elevating devices and other knots. Specifically on such camps high-quality joining of coils of pipes with flanges, branches, tees iron and other details, also their centering and adjustment is carried out. Rotary rollers allow to provide welding on prikhvatka, turning elements round own axis.
In common with camps different auxiliary devices, namely, the load-lifting mechanisms facilitating work and increasing productivity of work of camps are extensively used.
Unlike manual assembly "approximately" when differences from the drawing can make to 7-10 mm on pipeline meter, a tolerance on special boards – only 5 mm on the 3rd meters of the pipeline and 2 mm on each subsequent meter. But in any case the deviation more than 10 mm is not allowed.