When the PPR pipe is blocked due to the high temperature during welding, only use special scissors to subtract the blocked part and add the PPR fittings to re-weld directly.
Common sense of PPR pipeline welding construction and installation practices
1. General requirements
(1) The installer should be familiar with the general performance of the hot-melt plug-in connection of PP-R (random copolymer polypropylene) pipes, and master the basic operating points.
(2) The installer should be familiar with the design drawings, understand the structural process layout of the building and the mutual cooperation of other types of work.
(3) The materials, appearance and accessories should be inspected before construction, and it is forbidden to expose the cross-linked polypropylene pipe to sunlight for a long time. (4) A casing pipe should be installed where the pipeline passes through walls and plates. The inner diameter of the casing pipe should be 20mm larger than the outer diameter of the pipe. The casing should be filled with flexible non-combustible materials.
(5) All pipelines buried underground or concealed in walls or slabs must be subjected to a hydraulic test first, and they can be buried or sealed after passing the test.
2. Main points of piping
(1) The pipe should be cut by special cutting shears or ordinary hand saws. Make sure that the cut is flat when cutting the pipe. The section should be perpendicular to the pipe axis during shearing.
(2) Scrape a slope on the outer surface of the end of the pipe with a knife. Before welding, it is best to clean the welded part with alcohol, and then wipe it dry with a clean cloth or paper. And mark the length to be welded on the pipe.
(3) Turn on the special welding machine and heat it to 260°C. When the control indicator light turns green, start welding.
(4) Put the pipes and fittings to be connected into the welding head, and heat the outer surface of the pipe and the inner surface of the fitting interface. Then pull out from the machine head at the same time and quickly insert the heated end of the tube into the heated accessory interface. Do not rotate the tube during insertion. After insertion, it should be left to cool for a few minutes without moving. The heating time, cooling time and welding depth shall be implemented according to the following table:
Tube outer diameter (mm) 20 14 5 4 3
Welding depth (mm) 25 16 7 4 3
Heating time (s) 32 20 8 4 4
Processing time (s) 40 21 12 6 4
Cooling time (min) 50 22.5 18 6 5
Note: If the ambient temperature is less than 5℃, the heating time should be extended by 50%.
(5) After the fusion welding machine is used up, the head of the machine needs to be cleaned for the next use.
(6) Install the welded and connected pipe in place.