Piping connections of polyurethane insulated pipes commonly utilize welding. During the welding process, stringent requirements are placed on the handling of welds and the welding technique.
One, the quality of pipeline cut ends shall comply with the following specifications:
The cut surface should be flat, free of cracks, splits, burrs, unevenness, shrinkage, slag, oxides, iron filings, and other impurities.
The end face tilt deviation at the cutting end should not exceed 1% of the pipe outer diameter and must not be more than 3mm.
For those requiring bevel processing, the bevel processing method shall be carried out according to the welding plan specifications.
During pipe prefabrication, select the components of the pipeline according to the specified quantities, specifications, and materials as indicated in the single-line diagram. Additionally, label the system number of the pipeline as per the single-line diagram and indicate the sequence number of each component according to the prefabrication order.
During pipe prefabrication, the selection of free pipe sections and sealed pipe sections should be rational. The sealed sections should be machined according to the actual measured dimensions on site. After prefabrication, the internal cleanliness should be checked, the pipe ends sealed, and the sections stacked in order in a rational manner.
Four: The joint welding position of polyurethane insulation pipes should comply with the following regulations:
The pipeline location must be no less than the pipe's outer diameter or 100mm from the bend's starting point.
The distance between the two pipe joints should not exceed 5mm.
The location of the support bracket pipe must not coincide with the pipe joint weld; the distance between the weld and the edge of the support bracket must be no less than 50mm.
Pipe interfaces should avoid the locations of drain, vent, and instrument piping apertures, and should be no less than 50mm away from the edge of the aperture, as well as from the diameter of the hole.
Five, pipe support forms, materials, machining dimensions, and precision should be strictly made according to the relevant drawings. The working surface of sliding supports should be smooth and flexible, without any jamming.
