PPR Pipe With Low Temperature Brittleness
When the winter home is walking, the responsible business and the hydraulic master will not only pay special attention to the protection of the PPR pipe, but also explain to the owner the construction and maintenance of the pipeline, it is because the PPR pipe itself has the characteristics of low temperature brittleness, winter construction Need special care.
Perhaps the characteristics of the PPR Pipe you have heard many times, but PPR Pipe low temperature brittle in the end is how the matter?
PPR is a random copolymer of polypropylene, which is what we call the type Ⅲ polypropylene.
It is obtained by random copolymerization of propylene monomer and a small amount of ethylene monomer under heating, pressurization and catalyst. The ethylene monomer is randomly distributed to the long chain of propylene, wherein the vinyl monomer is generally controlled between 3-5%. Ethylene content and the polymerization of ethylene and propylene determines the characteristics of its low temperature brittleness.
PPR pipe due to low prices, the use of welding connection, is a cost-effective pipe. But if the procurement or construction is not standardized, the problems are more:
⑴ welding of the ring caused by large burr
In the hot melt, PPR Pipe heating time has strict rules. As the installation workers in the field can not accurately grasp the heating time, can not see the status of heating, so the quality of workers on the installation of a great impact on the quality.
⑵ PPR pipe welded pipe production is not much qualified, because one is the lack of parts; Second, the manufacturer in order to save material, the base with a very thin white metal, resulting in heavy light and unstable. Operation, often need another worker to help stabilize. As the welding device is not correct, the welding side of the tube when the heating is not correct, easy to make the connection skew, after a long time in the operation, due to the role of thermal stress leakage.
⑶ PPR pipe after cutting must also remove the burr, and the outer surface of the tube should also be scraping treatment, which can remove the outer surface of the tube oxide layer, while the welding of the annular burr is also smaller; but China's welding Generally do not have this set of scraping tools, and China's PPR pipe manufacturers to provide a larger pipe diameter error, so that the operator is not easy to grasp the amount of scraping.
⑷ Although the PPR pipe welding simple, but after heating, accurate and fast grasp the direction of the pipe is not easy to grasp. Because the tube and pipe heating softening, the connection time is very short, independent heating often use small diameter pipe, leaving only about 3 - 4 seconds time, in order to shorten the time to correct the pipe is not easy. So when the pipe connection is not correct, the installation of the entire pipeline system, the use of pipe cards will be three links, elbows and other fittings hard pull is, will make the pipeline system for a long time to withstand greater stress, resulting in some welding Position in a period of time after the prone to leakage.
⑸ some manufacturers to reduce the price competition and mixed with a lot of inorganic or waste plastics, resulting in pipe welding bonding performance decreased, life expectancy. Therefore, the proposed design, construction units and users in the procurement, PPR plastic pipe to the strict quality control. For example, we have purchased a different price of PPR pipe, making the same pipe section, are heated 5s fusion welding, quality products, all the connections in the twist after withstand the test, and poor quality products were screwed off or Pipe cracking.