Important role of cooling tube unit in ABA film blower

Important role of cooling tube unit in ABA film blower

The film tube of the plastic film blower gradually cools down to a certain temperature when it enters the traction wave from the head, which depends on the speed of the film blower tube, the thickness of the film tube, the extrusion temperature and the temperature inside the vertical cover.

The role of cooling devices is particularly important in high-yield equipment for the production of polyethylene film. In this device, the film is cooled by evenly blowing air in a very short path and its size is stabilized quickly, so there is no great distance to play before rewinding. Figure 38 shows a diagram of polyethylene film production with an air blowing unit. Compressed air with a pressure of 3 meters is fed into a distributor consisting of three concentric cylinders, and wells are fed into the cooling ring along eight hoses by the distributor. The cooling ring (Fig. 39) consists of two parts, which form an intricate path for balancing the air pressure evenly blown to the surface of the membrane tube of the cooled film blower through a 11.2mm annulus during assembly.

If the vertical cover is fully airtight, the temperature inside the vertical cover depends on the melt temperature, extrusion speed, diameters of film blower tubes, diameter of vertical cover, air density and thermal insulation of verdant wall. The cooling of the film tube of the film blower should reach the point where the folded caller tube does not "stick" on the traction roll. The "stick" of the film blower tube makes it difficult for the film to continue processing.

This type of co-extrusion head is the most advanced one in the world. Its superior axial co-extrusion structure overcomes many defects of the traditional cylindrical center symmetric radial co-extrusion head. The layers of moulds are superimposed axially in a conical shape, and the structure between layers can be combined arbitrarily: the number of layers can also be upgraded, the increase of layers does not affect the size of the outer diameter of the moulds, and there is no problem that the pressure drop of melt increases and the possibility of melt degradation increases with the increase of layers. The temperature of each layer can be controlled independently, so that different materials have more suitable temperature. At the same time, it is more convenient to clean the moulds.

Circulation of air around the membrane tube of a cylindrical film blower is not allowed at all. As a result of the air circulation, the film can be cooled unevenly along its periphery, resulting in uneven thickness.