Polyethylene pipes — what they are, where they are used, selection criteria

The production of polyethylene pipes usually includes several stages:

• extrusion: The initial step is extrusion, a process in which a polyethylene mixture is heated and pressed through a mold, creating long tubes. This process can use various methods such as extrusion using single or twin screw extruders.
• cooling and size setting: After extrusion, the pipe is cooled, allowing it to harden and retain its shape. This process also determines the final pipe size.
• cutting and processing: The pipes can then be cut to required dimensions and undergo further processing such as removing residual plastic and checking to ensure they meet quality standards.
• quality testing: Once manufactured, the pipes go through a testing process to ensure they meet quality and safety standards. This may include testing for strength, impact resistance, sealing and other characteristics.

Depending on the end product requirements and the manufacturer’s specifications, different methods and technologies may be used at each stage of production.

Types of polyethylene pipes

There are several different types of polyethylene pipes, each with their own unique properties and uses. The most common types of polyethylene pipes are:

• low pressure polyethylene (HDPE): HDPE pipes are flexible and durable, making them suitable for use in underground water lines, drip irrigation and other low-pressure applications.
• high-density polyethylene (HDPE): LDPE pipes have higher strength and rigidity compared to HDPE. They are often used in water supply systems, gas pipelines and industrial applications.
• medium pressure polyethylene (MDP): PSD pipes have medium strength and flexibility, making them a versatile choice for a variety of applications, including water supply, gas pipelines, heating mains and drainage systems.
• high density polyethylene (HDPE): HDPE pipes are highly durable, impact resistant and chemical resistant. They are widely used in pipeline systems for transporting water, gas, oil and other liquids and gases.
• cross-linked polyethylene (PE-PNS): This type of polyethylene pipes has improved mechanical properties and resistance to high temperatures. They are often used in hot water systems, district heating and industrial applications.

Each of these types of pipes has its own characteristics and advantages, which are determined by specific requirements and operating conditions. It should be noted that pipes made of low-density polyethylene (HDPE) are one of the most popular types of polyethylene pipes, especially in the field of water supply and drainage. Here are some reasons for their popularity:

• flexibility and lightness: HDPE pipes are highly flexible and light, which makes them easy to transport, install and lay, especially in hard-to-reach places.
• corrosion resistance: Polyethylene is a chemically resistant material that does not corrode, making it ideal for use in underground environments without the risk of deterioration or water contamination.
• strength and durability: HDPE pipes are highly durable and resistant to impact loads, allowing them to withstand earth pressure and transport water over long distances without leaks or damage.
• economic efficiency: HDPE pipes are often more economical than other types of pipes, making them an attractive choice for many projects.
• universal application: HDPE pipes can be used not only for water supply and drainage, but also for other applications such as gas supply, sewerage, irrigation, etc.

In general, HDPE pipes represent a reliable and universal solution for various infrastructure projects, which makes them widespread and in demand.

Note that production of HDPE pipes is somewhat different from the production of other polyethylene pipes, such as LDPE (high-density polyethylene) or PSD (medium-density polyethylene). The main differences are in the extrusion process and the raw materials used.

The main differences between the production of HDPE pipes and other types of polyethylene pipes may include the following:

• extrusion process: HDPE pipes typically use a low-pressure extrusion process, which provides greater flexibility and lower cost production compared to other extrusion methods used for HDPE and PSD pipes.
• raw materials: HDPE pipes are made from low-density polyethylene, which has a lower density and molecular structure than high-density or medium-density polyethylene, which also affects their performance and cost.

As for the demand for HDPE pipes, it can be explained not only by their relative cheapness, but also by their versatility, strength, corrosion resistance and chemical resistance. These factors make HDPE pipes an attractive choice for many infrastructure projects, especially in the field of urban and rural water supply and sewerage.

In what areas are polyethylene pipes used?