What are the requirements for PPR pipe welding quality?

What are the requirements for PPR pipe welding quality?
First, we must choose the quality of qualified hot melt welding machine.
The temperature control to correct. PP-R hot melt welding temperature: 253 -274. If the temperature is below 253 DEG C, the fitting and the pipe is only a thin surface layer of the melt, once between them for welding, the welding strength is not guaranteed, this is what we usually call the phenomenon of false welding; on the contrary, if the temperature is above 274 DEG C, molecule on the surface of pipe and pipe fitting was high the destruction of the PP-R formation of thin liquid, the connection will make the pipe diameter smaller PVC pipe manufacturers to remind the more important is that connection will occur brittle fracture, especially in the pipeline system completed after water pressure, often happen in this kind of problem.
The temperature will take a long time. The length of constant temperature is one of the important signs of the performance of hot melt welding equipment. Hot melt equipment, there is still a problem in energy consumption of heating to the set temperature, especially in winter, the air outlet, even in the non working gap, the heat consumption is great, and once during the operation, the pipes and fittings are respectively heat energy consumption, which requires a strong heat storage equipment ability and replenish ability.
Two, must choose qualified and suitable welding sleeve.
In the design, the qualified welding sleeve is fully considered the transverse structure and depth of welding, and the surface is not sticky and surface finish. At present, the domestic production of hot melt welding PP-R, PPC, PE and other manufacturers have hundreds of water pipes. Because of the various manufacturers of raw materials used in the production of pipe, different additives, different environmental conditions, different equipment, making the production of the pipe and pipe sizes are not the same. Therefore, the manufacturers and users of various pipe manufacturers must choose the suitable welding sleeve for the diameter of the pipe. For operators, after the final welding should be necessary to clean the surface of the welding sleeve, so as to avoid the welding part of impurities.
For more than 40mm diameter pipe welding, due to the larger caliber, non personal strength can work, must use mechanical equipment to ensure that the pipe into the pipe depth and straightness. We found that in many sites with five to six workers on a 110mm caliber welding interface, cost tremendous effort can not guarantee the pipe straightness and the insertion depth, the entire pipeline winding, it is difficult to imagine in a certain temperature and pressure condition.
Three, hot melt welding prone to problems.
It should be said that in strict accordance with the welding process and welding technology requirements of the construction operation of the pipeline system, the use of normal temperature and pressure will not have any problems. But in our daily construction is often found in burst phenomenon or will trachoma in connection pipe and pipe fitting.
The main reasons are as follows:
The temperature of hot melt welder is not correct, too high or too low, the change of the properties of polypropylene;
The welding surface does not handle well, shedding or surface coating and the pipe part makes contact hole;
The welding set the wrong size, design right, the melting depth and weld pipe connecting structure is not appropriate;
The welding of pipe before welding surface cleaning;
The welding pipe and pipe fittings not maintain concentric or straight line.
Four, the correct welding procedure.
The hot melt weld preparations
The 25-110mm diameter pipe to the pipe chamfering device port half chamfer angle of 15 DEG to the original pipe wall thickness;
Clean the surface of the welding part of the pipe with a cleaner (or alcohol) and a brush;
When the pre assembled parts are welded, the connection is made on the position of the pipe and pipe fitting.
The 40mm caliber above must use the plane and vertical pipe welding welding machine;
Every time the dissolved, should use dry cloth or paper to wipe the heating cover and the heating head, do not use cleaning agents.
The hot melt connection and
After the pipe and the pipe are respectively inserted into the heating sleeve and the heating head, do not rotate or move too fast.
After heating, remove the pipe and fittings from the heating element.
Immediately after heating pipe and fittings along the axis pressure, do not rotate. Strictly adhere to the hot melt welding standard holding time and cooling time.

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