EXTRUSION HEAD FOR MANUFACTURING HOSE OF POLYMERIC FILM Russian patent published in 1994 - IPC

FIELD: forming of plastics. SUBSTANCE: extrusion head has core with outer surface provided with multistart grooves. The number of starts is at least eight, radius of groove is chosen in the ratio of 1/20 - 1/25 with respect to core diameter, with depth of groove being gradually decreasing. Evaporation chamber is disposed in the upper part of core. Core central opening for feeding polymer melt is connected via radial openings with helical groove coils. Tip with casing and core define annular double- sided cone supply slit by their surfaces. Section of forming slit and supply slit maximum section are chosen in the ratio of 1/10-1/30. Height of forming slit is equal to or less than that of supply slit. EFFECT: high quality of film hose material by providing complete homogeneity of melt and uniform dispensing. 2 cl, 4 dwg