The development history, application scope and product characteristics of PE pipe

Since the 1990s, our country's synthetic resin industry has developed rapidly, and both production and consumption have shown a good growth trend. It is now ranked fifth in the world. However, there is a large supply gap for various types of special resins that plastic pipes rely on. Although the production of PE and PP resins in our country is considerable, it is still suitable for pipe manufacturing, especially the special materials for PE pipes required for urban water supply and gas transportation, as well as the special materials for building hot and cold water. PP-R special materials are still relatively scarce, and a certain amount has to be imported from abroad every year to meet the demand. It is in this context of the industry, HDPE steel mesh skeleton composite pipe with its excellent performance, stand out in many plastic pipe products, and gradually emerge.
, application range Our country's synthetic resin industry has flourished since the 1990s, rising in the global rankings. However, the supply of plastic pipe special resin short board has become increasingly prominent. Although China has a certain scale in the production of PE and PP resins, it can really meet the strict requirements of pipe production, especially the special materials for PE pipes required in key areas such as urban water supply and gas transportation, as well as the special materials for PP-R used in building hot and cold water systems. However, it is extremely scarce, and imports have become an important way to make up for the gap. Second, the development of pipelines Our country's plastic pipe industry has a strong development momentum in recent years, and the quality of products is also continuing to improve. Among them, polyethylene PE pipes, such as the AD PE pipes under Hubei AD Building Materials Co., Ltd., have been widely used in many fields by virtue of their own series of unique advantages. In the field of construction, it covers building water supply, drainage, buried drainage pipes, building heating and gas transmission pipes; in the industrial field, it plays an important role as an electrical and telecommunications protection casing and industrial pipes; in the agricultural field, it has become a high-quality choice for farmland irrigation pipes. Especially in important fields related to people's livelihood and infrastructure such as urban water supply, gas supply and farmland irrigation, AD PE pipes play an indispensable key role. III. Product Features (1) Corrosion Resistance Polyethylene has excellent corrosion resistance, and at the same time has good hygienic properties and long service life. It is a non-inert material, except for a few strong oxidants, can withstand the erosion of a variety of chemicals, and is not easy to breed bacteria. Compared with traditional steel pipes and cast iron pipes, plastic pipes show significant advantages in terms of water transportation energy consumption, living energy consumption, weight, water flow resistance, installation convenience, cost, life and thermal insulation function. International standards and some foreign advanced standards have clearly recognized that the service life of polyethylene pipes can reach more than 50 years, and this conclusion has been fully verified in practical applications. In addition, polyethylene can be widely used, and another important reason is that PVC is facing increasing pressure in environmental protection. On the one hand, PVC itself has hidden concerns in terms of hygiene performance. Although PVC pipes can meet the hygiene requirements in the drinking water field under regular production and strict control, there are still some worrying problems in the actual production process, such as excessive vinyl chloride monomer in PVC resins, the possible misuse of toxic additives in the formulation of PVC pipes for water supply, and even the wrong application of PVC pipes and pipe fittings for drainage that are not guaranteed to be non-toxic to water supply pipes and pipe fittings. On the other hand, there are also difficulties in the recycling of PVC pipes. PVC is a thermoplastic like polyethylene, and it has the possibility of recycling in theory. However, the practice of various countries shows that the proportion of old plastic products that can actually be recycled is very limited. The main treatment method is incineration to recover energy. However, because PVC contains chlorine, if it is not properly controlled during incineration, it is very likely to produce harmful substances, while polyethylene contains only carbon and hydrogen, and only water and carbon dioxide are generated after incineration, which is more friendly to the environment. (2) Flexibility and scratch resistance Polyethylene has unique flexibility and excellent scratch resistance. The flexibility of its piping system has great technical and economic value. Good flexibility allows polyethylene pipes to be rolled up and supplied in longer lengths, thus avoiding the use of a large number of joints and pipe fittings. Take Nantong Water Supply Company, a national urban water improvement demonstration unit, as an example. In the one-meter-per-household renovation project, they made full use of the coiling characteristics of PE small-diameter pipes. From the water meter to the user, a pipe is directly connected to the bottom, without pipe joints in the middle. This approach not only saves costs, but also significantly improves work efficiency. This feature has also been widely recognized by water supply companies in cities across the country that carry out water meter projects, and has become their preferred product for water improvement operations. At the same time, the flexibility, light weight and excellent scratch resistance of polyethylene pipes enable them to use a variety of installation methods that have less impact on the environment and social life and are cost-effective. Among them, the no-excavation construction technology is a typical representative. Excavation-free construction technology refers to the use of various rock and soil drilling techniques to lay, replace or repair various underground pipelines under the condition of no trenches on the surface. A variety of excavation-free construction technologies, such as horizontal directional drilling and guided drilling methods for laying new pipelines, in-situ replacement of old pipelines, interspersed and updated lining methods for repairing old pipelines, and various improved lining methods (folding deformation method, hot drawing method and cold rolling method), are very suitable for the use of polyethylene pipes. From a practical application point of view, plastic buried pipes are "flexible pipes". Under the premise of correct design and laying construction, they can bear the load together with the surrounding soil. The pressure relaxation characteristics of polyethylene can effectively dissipate stress through deformation, and its actual axial stress level is much lower than the theoretical calculation value. Moreover, the elongation at break of polyethylene pipes is generally greater than 500%, and the bending radius can be as small as 20-25 times the diameter of the pipe. It is a kind of high toughness material, and it has strong adaptability to uneven settlement of the foundation. In the Kobe earthquake in Japan in 1995, PE water supply pipes and gas pipes became the only piping system that survived, which fully demonstrated its excellent performance in dealing with extreme situations. (3) Low temperature resistance Polyethylene has extremely outstanding low temperature resistance. The low temperature embrittlement point of PE pipes is -70 ° C, which is obviously better than other pipes. During field construction in winter, polyvinyl chloride (PVC-U) pipes are prone to brittle cracking. In the pilot project of laying polyvinyl chloride (PVC-U) buried water supply pipes in Beijing, our country has summed up an experience, that is, when the temperature is below zero, it is not suitable for laying polyvinyl chloride (PVC-U) pipes. In addition, an obvious contrast is that in order to improve the toughness and low temperature impact resistance of PP, ethylene and propylene monomer are usually copolymerized to make random copolymer polypropylene (PP-R). It generally adopts the process route and method of iPP to copolymerize the mixed gas of propylene and ethylene to obtain a copolymer with random distribution of propylene and ethylene segments in the main chain (ie PP-R pipe material). The ethylene content in PP-R pipe material is mostly around 3%. However, even after such improvement, the low temperature resistance of PP-R is still unsatisfactory. Its embrittlement point is about -15 ° C, which is much higher than the embrittlement point temperature of polyethylene pipe - 70 ° C. (4) Crack growth fracture toughness Polyethylene has good rapid crack growth fracture toughness. When rapid crack growth failure occurs, the crack can rapidly expand at a speed of 100-45m/s, and the distance can reach hundreds of meters or even more than ten kilometers, which will cause damage to long-distance pipelines, leading to large-scale leakage accidents, and subsequent possible combustion explosions (in the case of natural gas transportation) or floods (in the case of water transportation) accidents. Although the probability of such accidents is not high, once they occur, the harm caused will be extremely serious. For the continued development of plastic pressure pipes, the importance of preventing rapid crack growth failure has exceeded the requirements for long-term life strength performance. The reason is that under the same SDR (pipe diameter to thickness ratio), the calculated long-term life-long strength is not associated with increasing the pipe diameter (in fact, large-diameter pipes may be safer than small-diameter pipes), but the risk of rapid crack growth increases with the increase of the pipe diameter. In the existing large varieties of plastic pipes, such as polyethylene, polypropylene, PVC pipes, etc., when the pipe diameter reaches a certain level, the allowable pressure determined by preventing rapid crack growth and damage is always lower than the allowable pressure determined by the long-term strength problem. This means that after determining the allowable pressure according to the requirements for preventing rapid crack growth and damage, the long-term life requirements (e.g. 20 ° C, 50 years) can be satisfied by themselves; and those materials with poor fracture toughness due to rapid crack growth will gradually be eliminated from the market, regardless of their long-term strength properties. For example, polyvinyl chloride (PVC-U) gas pipes have been basically replaced by polyethylene (PE) gas pipes. In Europe, the trend of polyvinyl chloride (PVC-U) water supply pipes being replaced by polyethylene (PE) pipes has also been very obvious. It is worth noting that our country has not yet established a test device for monitoring rapid crack growth and damage, and our country's plastic pressure pipe standards do not address this issue, which also reflects the level of plastic pressure pipes in our country compared to the world's general level, at least one stage behind the development stage. (5) Polyethylene Pipe Installation The installation and connection of polyethylene pipes is convenient and reliable. It can obtain a reliable and solid connection between the inner surface and the original pipe through the more convenient hot melt docking and socket method (the connection will form a small welded raised ring), or special electrofusion pipe fittings can be used to connect polyethylene pipes. For small diameter pipe, can also adopt Hubei AD Building Materials Co., Ltd. introduction of patented technology production of card type connection, this connection method is not only convenient and reliable, but also has been widely used in many of our country water division of one household one meter project. Polyethylene pipe welding joint with the ability to withstand axial load without leakage and disengagement. Source: Hubei AD Building Materials Co., Ltd., welcome to share! Hubei area PE pipe, AD PE water supply pipe consultation hotline: 17399989993