Apparatus for heating film sectors of a tubular film web extruded from a film blowing head

摘要

An apparatus for heating the film sectors of a tubular film web of a thermoplastic synthetic material extruded from a film blowing head of a blown film extruder installation, is provided with nozzle rings delimiting the exit gap of the film blowing head at least the outer ring whereof is divided into temperature-regulating sectors, which apparatus is provided with temperature-regulating elements and devices controlling their temperature. To allow the film sectors to be rapidly heated in the way required according to the control inputs of the regulating procedures, the temperature-regulating elements consist of ultrasonic and/or microwave heating elements.