Spiral welded pipe equipment within the anti - corrosion treatment Detailed

 Construction Conditions of Anticorrosion Coatings in Spiral Welded Pipe Equipment

      Cement mortar fabric construction, usually under the spiral pipe should be completed, test pressure qualified and requested by the compaction after compaction rammed. Fabric construction process, the pipeline is necessary to be in a stable situation. Assuming the first fabric after the next layer of corrosion, because the steel wall thin, small stiffness, in the construction of lifting, transportation, soil is also a large deformation and damage to the coating.

      Before the construction of the fabric, the inner wall of the pipe is necessary to clean, remove the soft oxide, floating rust, dirt, grease, welding slag and other attachments; steel wall of the protrusion should not be greater than the thickness of the coating planning 1/3; Vertical deformation shall not be greater than the planning rules, and not more than 2% of the pipe diameter.

Construction of Anticorrosion in Spiral Welded Pipe Equipment

     Cement mortar coating can be used mechanical spraying, artificial pressure relief, dragging drum or centrifugal prefabrication method construction. Assuming the need to use prefabricated anti-coating method, in the transport, installation, backfill process should be used to protect the protective measures.

Construction, the main mix of cement mortar, cement and sand quality cooperation ratio of 1: (1-2), cement mortar slump of 60-80 mm, cement mortar compressive strength should not be less than 30 MPa.

Mechanical coating method of cement mortar within the coating surface smooth, fine, uniform thickness, the role is better. Foreign 1930s initially selected mechanical spraying construction, China since the 60's has successively in Shanghai, Qingdao, Dalian and other cities. When elective mechanical spraying method is used, the elbow, the tee, the special pipe and the gate valve can be used to modify the craft, and the smooth mutation section is connected with the mechanical sprayed fabric.

Others, drag towers or centrifugal prefabrication methods are also widely used, no longer specifically described here. Regardless of the method of construction, the protection process is to ensure that the cement mortar coating does not occur cracks and hollowing the key link. Therefore, the cement mortar within the coating after forming, it is necessary to immediately block the pipeline, shall not constitute air convection; after the final condensate wet protection, the general protection of Portland cement should not be less than 7d, slag Portland cement should not Less than 14 d; water should continue to block before, adhere to the wet.

Construction Quality of Coatings in Spiral Welded Pipe Equipment

The quality of the coating within the cement mortar shall conform to the following rules.

① The width of the crack shall not be greater than 0.8 mm, the longitudinal length along the pipe shall not be greater than the circumference of the pipe and shall not be greater than 2.0 m.

② coating thickness of the allowable error and pitting, empty dots and other surface defects should be the depth of the rules, defect area should not be greater than 5 cm2 each.

③ flatness plead to 300 mm long ruler, along the longitudinal axis of the pipe attached to the wall, measuring the surface of the coating and the distance between the ruler should be less than 2 mm.

④ empty drum area per 1 m2 shall not exceed 2, each shall not be greater than 100 cm2.