Three major devices of twin-screw extruder granulator

The cooling device of the twin-screw extruder granulator. After the formed plastic extrusion layer leaves the machine head, it should be cooled and shaped immediately, otherwise it will be deformed under the action of gravity. The cooling method is usually water cooling, and according to the water temperature, it is divided into rapid cooling and slow cooling. Rapid cooling is the direct cooling of cold water. Rapid cooling is beneficial to the shaping of the plastic extrusion coating. However, for crystalline polymers, due to rapid heat cooling, internal stress is likely to remain in the structure of the extrusion coating, resulting in cracks during use. Generally, PVC The plastic layer is quenched. Slow cooling is to reduce the internal stress of the product. Water with different temperatures is placed in the cooling water tank in sections to gradually cool down and shape the product. The extrusion of PE and PP is carried out by slow cooling, that is, through hot water, warm water and cold water. Three-stage cooling.

Twin-screw extrusion granulator preheating device, cable core preheating is necessary for both insulation extrusion and sheath extrusion. For the insulation layer, especially the thin layer insulation, the existence of pores cannot be allowed. The wire core can be completely removed from the surface water and oil by preheating at high temperature before extrusion. For sheath extrusion, its main function is to dry the cable core to prevent the possibility of pores appearing in the sheath due to the action of moisture (or moisture surrounding the cushion). Preheating also prevents the effect of residual internal pressure due to quenching of the plastic during extrusion. In the process of plastic extrusion, preheating can eliminate the huge temperature difference formed when the cold wire enters the high temperature die and contact with the plastic at the die mouth, avoiding the fluctuation of the extrusion pressure caused by the fluctuation of the plastic temperature, thereby stabilizing the extrusion volume and ensuring Extrusion quality. The electric heating wire core preheating device is used in the extrusion unit, which requires sufficient capacity and ensures rapid temperature rise, so that the wire core preheating and cable core drying efficiency is high. The preheating temperature is restricted by the pay-off speed, and is generally similar to the temperature of the machine head.

The straightening device of twin-screw extrusion granulator, one of the more common types of plastic extrusion waste is eccentricity, and the bending of various types of wire cores is one of the important reasons for insulation eccentricity. In jacket extrusion, scratches on the jacket surface are also often caused by bending of the cable core. Therefore, straightening devices in various extrusion units are essential. The main types of straightening devices are: drum type (divided into horizontal and vertical); pulley type (divided into single pulley and pulley group); Press wheel type (divided into horizontal type and vertical type) and so on.