PLANT FOR THE PRODUCTION OF PLASTIC TUBULAR FILMS WITH A BIAXIAL ORIENTATION AND AN IN-LINE STABILISATION PHASE

摘要

A plant for the production of plastic tubular films with a biaxialorientation,comprising one or more extruders to feed the molten polymer to an extrusionhead;an annular drawplate for extruding a tubular;an orientation station in which the tubular is heated, expanded by an airbubbleand simultaneously stretched in an axial direction, wherein means areprovided,suitable for compensating the volume of inflation air so as to maintain aconstantpressure inside the tubular during the orienting process.To this end at least one of the pairs of rollers that feed and pick-up thetubular ismobile in a direction parallel to the axis of the tubular, and means areprovidedto command the shifting of the said pair of rollers depending on the diameterofthe tubular measured during the orienting phase.