EN 
简体中文Twin-screw extruders have two identical screws that intermesh, housed in a matching barrel. Screws and barrels can be parallel or conical. During twin-screw extrusion – PVC / C-PVC is conveyed, compressed, degassed, plasticized, sheared, kneaded, blended at an optimal level and homogenized before entering the die. If the "screw flight paths" intersect, the screws are said to intermesh.
Screws are said to be fully engaged if the threads intersect in such a way that the tip of the thread of one screw nearly touches the bottom of the channel or root of the other screw. This clearance is called the "milling clearance". Fully intermeshing, counter-rotating twin-screw extruders are essentially friction-independent positive displacement pumps designed for heat-sensitive polymers such as PVC or C-PVC.
Due to the clearance between the screw flight and the barrel, full positive displacement cannot be achieved. Therefore, as the clearance increases due to wear, the output also decreases. Both parallel and conical screws are used for processing U PVC. Conical extruders were pioneered by Cincinnati, while many manufacturers like Battenfeld have introduced parallel screw extruders.
In conical extruders, the extruder is specified by the diameter of the screw at the end of the metering section. Meanwhile, the size of the parallel extruder is the diameter of the thread. In conical extruders, the plasticizing rate of PVC is mainly controlled by controlling the temperature of the screw and barrel, rather than by shearing, which helps to significantly reduce the current intensity and increase the Power economy.
No.8#,1st Branch, Lingang 2nd road, Shuangqiao Industry Zone, Dinghai Zhoushan, Zhejiang, China
+86-580-8058728
+86-580-8058708
