What are the differences in cooling systems among different types of Dalian blown film units?

As a key equipment for plastic film production, the performance and quality of the blown film unit directly affect the production efficiency and product quality of the film. With the advancement of technology and the continuous changes in market demand, blown film units are constantly developing in terms of high efficiency, energy saving, intelligent control, multifunctionality, and environmentally friendly materials, providing various industries with higher quality and more environmentally friendly plastic film products. In the future, blown film units will continue to play an important role in technological innovation and product upgrades, promoting the sustainable development of the plastic film industry.

According to the direction of film blowing, it can be divided into upward blowing method, downward blowing method, and flat blowing method. The upward blowing method is suitable for producing wide film with good film cooling effect, but the equipment height is relatively high; The down blowing method is easy to operate and maintain, and is commonly used for producing ultra-thin films; The flat blowing method equipment has a simple structure and a small footprint, but the film cooling is uneven, making it suitable for producing small and medium-sized films.

What are the differences in cooling systems among different types of Dalian blown film units?

Wind ring type

Single screw blown film unit: Medium and low-end single screw blown film units often use a simple and inexpensive single air outlet wind ring, which controls the cooling effect by adjusting the air volume. High end single screw blown film units may be equipped with dual outlet air rings, with separate upper and lower air outlets, and some may also be equipped with jet rings, which can adjust the air volume and angle of the main and auxiliary air outlets respectively, achieving stepped cooling of film bubbles and improving cooling efficiency.

Twin screw blown film unit: Usually, suitable air rings are selected according to production needs. Due to the strong production capacity of the twin-screw blown film unit and the high requirement for cooling effect, double port air rings or rotating air rings are often used. The rotating wind ring consists of a main structure, a driving system, and an auxiliary system. The wind ring body can rotate to evenly blow cooling air towards the surface of the film bubble, solving the problem of uneven film thickness and improving film quality.

Multi layer co extrusion blown film unit: In order to meet the requirements of high-speed production and high-quality films, the cooling method of IBC internal cooling air ring combined with external cooling air ring is often used. The IBC internal cooling air ring consists of a cooling water channel system, a double-layer air duct design, and a temperature control module. It is an efficient cooling device that combines internal cooling (water cooling) and external cooling (air cooling), suitable for film production of high-capacity or high viscosity materials, and can significantly improve cooling efficiency.

Cooling medium

Single screw blown film unit: Generally, air is used as the cooling medium, and the cooling air is blown towards the film bubbles through an air ring for cooling. The feeding section of some machine barrels adopts forced water cooling to control the temperature of the barrel.

Twin screw blown film unit: also mainly using air cooling film bubbles, some twin screw granulators use electric heating and water cooling to automatically control the temperature of the barrel and screw. Each section of the barrel cooling pipeline is equipped with manual shut-off valves and solenoid valves to adjust the temperature by controlling the flow rate of soft water.

Multi layer co extrusion blown film unit: In addition to using air cooling, the IBC internal cooling air ring uses cooling media such as water or oil to circulate inside the air ring, cooling the air ring body and achieving efficient cooling. In addition, the cooling steel roller adopts a bidirectional circuit design inside, with a built-in spiral flow channel that introduces cooling water to ensure uniform temperature on the roller surface, used for cooling the thin film passing through.

Cooling method

Single screw blown film unit: mainly for external cooling, blowing cooling air through the air ring to cool the outer surface of the film bubble. Some advanced models may combine internal cooling by introducing a certain amount of cooling air into the membrane bubble, but the effect of internal cooling is relatively weak compared to external cooling.

Twin screw blown film unit: Similar to single screw blown film unit, it mainly uses external air cooling and internal cooling as a supplement. However, in some special cases, such as the production of high viscosity materials or high requirements for film performance, the design and application of internal cooling will be strengthened.

Multi layer co extrusion blown film unit: adopts a combination of internal and external cooling, with external air cooling through an air ring and internal cooling through an IBC internal cooling system. This combined cooling method can better control the temperature and thickness uniformity of the film bubbles, improving the quality and performance of the film. At the same time, a special cooling method is also used for the cooling steel rollers in the multi-layer co extrusion blown film unit to ensure that the film can be fully and uniformly cooled before winding.

The blown film unit heats and melts plastic raw materials through an extruder, and then extrudes them into tubular films through a die. At the same time, compressed air is introduced from the center of the mold to inflate the tubular film to the desired size and thickness. During the inflation process, the film is cooled and shaped by a cooling air ring, and then pulled by a traction device to a winding device to be wound into a film roll.

The film produced by the blown film unit is widely used in fields such as food packaging, daily necessities packaging, and industrial packaging. Thin films have good transparency, strength, and sealing properties, which can effectively protect products from external pollution and damage. Agricultural film is mainly used for greenhouse covering, plastic film covering, etc. The film has good light transmittance, heat preservation and anti-aging properties, which can improve the yield and quality of crops.