Injector for feeding additives in a polymer melt stream

摘要

The injector is a round plug, tapered to fit tightly into a mating tapered hole across the bore carrying the melt. Additive is pumped via a small funnel (2) into an axial bore (3) through the plug that meets another bore at right angles to it leading to the nozzle (6). The portion of the plug inside the melt bore has a waist (4) formed into it so that the melt flows evenly around the nozzle. This waist has an elliptical cross-section and the additive flow to the nozzle is along the major axis so that the nozzle has sharp edges. Preferred Features: The plug is tapered at an angle = 5-15 degrees . A slot (5) in the base of the plug locates it in the bore of the melt.