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Polyethylene (PE) is a thermoplastic resin, first produced in 1933. In the next 20 years, chemists in the petrochemical industry advanced the manufacturing process to reduce costs while obtaining better grades. In the early 1950s, Phillips Petroleum chemists developed an economical process and provided a new type of polyethylene called high-density polyethylene (HDPE). At that time, various grades of PE could be produced, and soon the resin was used in various products and applications.
The first use of HDPE was for baby bottles. Using it to replace glass is the beginning of HDPE to replace traditional materials because it improves physical properties. It will not break like glass, the production cost is lower, and it is safer. Today, HDPE has replaced glass used for bottles and metals, used in barrels, barrels, and gas tanks, and it is used in many other applications, including packaging and piping components and systems. According to the US "Plastics News" report in December 2016, HDPE sales in North America and Mexico have been close to 16 billion pounds, and more production capacity will be put into production this year. HDPE history For pipes, the HDPE grades used now are different from earlier materials, and even completely different from other HDPE materials used in consumer applications today. Pipe-grade HDPE is a highly engineered compound designed for long-term service in critical applications. Before it can be used in manufacturing, it goes through a series of rigorous testing procedures.
In the late 1950s, solid-walled HDPE pipes began to replace metal pipes in oil and gas collection systems. In the early 1960s, natural gas companies began to replace failed iron pipes with PE pipes, and due to its successful performance history, 95% of all new gas distribution systems currently installed use PE pipes. Soon, corrugated HDPE pipes began to replace clay pipes in agricultural drainage systems. In the late 1980s, large-diameter corrugated HDPE pipes began to replace metal and concrete in rainwater culverts. The material continues to develop into the current third and fourth generation developments, each with improved performance. Thermoplastic piping systems are sustainable and environmentally friendly to piping selection.
They have high energy efficiency during manufacturing and provide peak protection during use. Compared with metal or concrete alternatives, they also require less energy than manufacturing, transportation and installation. The plastic piping system has corrosion resistance and wear resistance, long service life, excellent joint performance, and no leakage protection, making it of good value. For centuries, farmers have known that proper field drainage and irrigation are key parts of increasing crop yields, so they use clay bricks. Studies have shown that when the field is "flattened", soybean yield increases by 43% and corn yield increases by 30%. With the advent of HDPE resin and the ability to manufacture bellows, the agricultural market has become the starting point for more pipeline development.
In less than a generation, corrugated HDPE pipes have replaced products that have been in use for hundreds of years. Soon after, the larger diameter provided new applications, especially in the transportation sector and other public storm drainage projects. Polymer Performance Pipeline HDPE resin is a compound composed of PE copolymer (also known as resin), which is added with colorants, stabilizers, antioxidants and other ingredients to enhance the properties of the material. This formula produces HDPE pipe, which is tough, durable and strong. HDPE pipes are almost entirely classified as thermoplastics because they soften and melt when heated sufficiently, and then harden when cooled. This process can also be reversed, allowing the resin to be recycled into other applications at the end of the pipe’s life.
As a material that has been extensively tested, HDPE pipe provides widely documented performance and is continuously verified through continuous laboratory research and decades of field service. Design engineers in other utilities continue to discover advantages and determine new uses for HDPE products. For example, because PE used in pipe production is an engineering resin, it provides a favorable strength-to-weight ratio for the pipe.
Some of the reasons for the wide and diverse applications of HDPE pipe include the material's ease of handling and resistance to soil, chemicals, environmental water and moisture, and the fact that it will not corrode or rust. Since HDPE is a non-conductor of electricity, it is not affected by electrochemical-based corrosion processes caused by electrolytes such as salts, acids and alkalis. HDPE pipes are not susceptible to biological attack or agglomeration, can resist biological clogging, and maintain a high, consistent flow throughout the life of each system. This means less wear and tear and saves a lot of costs for running utilities.
In addition to the standards used to manufacture corrugated HDPE pipe materials, it is important to note that the pipes are manufactured and certified in accordance with many industry standards such as AASHTO, ASTM, CSA Group and American Railway Engineering and Maintenance. In addition, it has been approved for use by the Federal Aviation Administration, the Department of Transportation, and other federal and local agencies. These national standards are regularly reviewed by various industry organizations and their members. Constantly strive to keep the standards up to date, enhance and strengthen testing standards, and advance raw materials and post-manufactured pipelines. The test protocol can be extensive and extreme. By submitting products and passing independent tests, manufacturers assure customers that their products meet the requirements of the standard, including physical properties, connection and installation methods.
Initially, the only connection mechanism for corrugated HDPE pipes was a connector that held two flat-end pipes together to form an anti-fouling connection. When mating connections in the field and other applications, this type of coupler is still often used in agricultural applications. In the 1980s, a higher integrity joint was formed between the pipe sections, and a bell-jar coupling system was used, which is usually used more for sewage sewers than rainwater drainage systems. Then complete the integral bell and sleeve coupling. This is the most commonly used connection method for double-wall corrugated HDPE pipes. The next-generation coupling has an extended inner sleeve to provide more joints for the official segment.
The practicality of HDPE and polypropylene piping systems has been recognized. These materials are now used in sewer and drainage works. The availability of resins is increasing, pipe manufacturers are increasing production capacity, and new developments in raw materials and piping system design show that thermoplastic pipe applications are smart and reliable choices. The industry will continue to participate in progress-just as the industry has been in development for more than half a century. As a thoroughly reviewed and progressive solution, thermoplastic piping systems will provide services and meet the needs of all generations of the world.