How does cooling water temperature affect the cooling and quality of PE pipe extrusion production line?

After PE pipe extrusion line, the extruded thermoplastic parison needs to enter the cooling device immediately for rapid cooling to lock the geometric shape and size of the pipe. In this cooling and shaping process, the choice of cooling water temperature is directly related to the cooling speed and cooling uniformity of the pipe, which in turn affects the mechanical properties and surface quality of the pipe.

The wall thickness of PE pipe is relatively thick, which leads to its relatively slow cooling and shaping speed. In order to ensure that the inside and surface of the pipe can achieve the ideal cooling effect, a longer production line is required to provide sufficient cooling time. The cooling water temperature directly affects the rate of this cooling process.

When the cooling water temperature is too high, the temperature difference between the pipe and the cooling medium decreases, the heat exchange efficiency decreases, and the cooling speed of the pipe slows down. This will not only extend the production cycle and increase production costs, but may also cause excessive internal stress in the pipe due to insufficient cooling, affecting the mechanical properties and long-term stability of the pipe.

On the contrary, when the cooling water temperature is too low, although the cooling speed of the pipe can be accelerated, too fast cooling may cause a large temperature difference between the surface and the inside of the pipe, resulting in internal stress concentration and increasing the risk of cracking of the pipe. In addition, too low cooling water temperature may also cause the surface of the pipe to harden rapidly, forming a hard shell, which hinders the effective dissipation of internal heat and causes uneven cooling.

Given the important influence of cooling water temperature on the cooling speed and final quality of the pipe, it is crucial to select the appropriate cooling water temperature and precisely control it. For PE pipes, the selection of cooling water temperature should take into account the following factors:
Pipe wall thickness: The thicker the pipe wall, the longer the cooling time required. The cooling water temperature can be appropriately lowered to speed up the cooling speed, but care should be taken to avoid too low a temperature that causes internal stress concentration.
Production speed: The faster the production speed, the higher the temperature of the extruded pipe, and the higher the requirement for cooling water temperature. At this time, the cooling water temperature can be appropriately increased to increase the heat exchange efficiency, but the cooling uniformity must be ensured.
Material properties: The thermal conductivity, melting point and other physical properties of PE materials will also affect the cooling speed. According to the specific material characteristics, adjust the cooling water temperature to achieve the best cooling effect.
Production environment: external conditions such as ambient temperature and humidity will also affect the cooling effect. In high temperature and high humidity environments, it may be necessary to appropriately reduce the cooling water temperature to maintain a stable cooling rate.
In actual production, in order to ensure the precise control of the cooling water temperature, the following measures are usually required:
Cooling water circulation system: Establish a cooling water circulation system to achieve precise control of the cooling water temperature by adjusting the flow and temperature of the circulating water.
Temperature sensor and control system: Install a temperature sensor in the cooling device to monitor the cooling water temperature in real time, and automatically adjust the supply and temperature of the cooling water through the control system to ensure that the cooling water temperature remains within the set range.
Regular maintenance and inspection: Regularly maintain and inspect the cooling device to ensure the normal operation and cleanliness of the cooling water circulation system to avoid the cooling effect being affected by scale, impurities, etc.
Optimize the layout of the production line: According to factors such as the wall thickness and production speed of the pipe, reasonably design the layout of the production line to ensure that the pipe has enough residence time in the cooling device to achieve the ideal cooling effect.
By accurately controlling the cooling water temperature, the production efficiency and final quality of PE pipes can be significantly improved. Specifically, a reasonable cooling water temperature can:
Improve production efficiency: speed up the cooling speed of the pipe, shorten the production cycle, and improve production efficiency.
Optimize pipe quality: ensure that the pipe interior and surface can achieve the ideal cooling effect, reduce internal stress concentration and cracking risks, and improve the mechanical properties and long-term stability of the pipe.
Reduce production costs: reduce energy waste and scrap rate by optimizing the cooling process, and reduce production costs.
Improve product competitiveness: high-quality PE pipes can meet a wider range of application needs and enhance the market competitiveness of products.