METHOD OF CONTROL OF JOINT EXTRUSION OF PLASTICS BY MEANS OF THROTTLE VALVE FOR MOLDING THEM AND DEVICE FOR ITS EMBODIMENT Russian patent published in 2001 - IPC

FIELD: joint extrusion of two and more flows of plastics or their analogues for introducing them into molding unit. SUBSTANCE: method includes combining flows of plastics with at least one center flow which is used for performing function of core of plastic article being molded. Core is located inside inner and outer flows of plastic which are used as cover layers. Then, flow of combined jets over concentric circular paths is limited inside and along passage of flow extended longitudinally towards mold gate. Circular core flow is enclosed in inner and outer circular layers of flows of cover plastic. Then, concentric circular flows are branched in area of gate in opposite transversal directions for injection into respective opposite transversal sections of cavity. Device for method embodiment includes sources of plastic flows, units for combining flows with at least one center flow, hollow passage extended longitudinal and connected with combining devices for receiving outer and inner flows and flow limiting units which are located along and inside passage for making combined flows run over concentric circular paths inside passage of tubular extruder to are of mold gate. Device is also provided with units for branching concentric circular flows in opposite transversal directions for injection into respective opposite transversal areas of cavity. Branching units are located in gate area. EFFECT: possibility of obtaining homogeneous mold article; extended range of material and temperatures of performing the process. 29 cl, 34 dwg