DEVICE AND METHOD FOR THE ADJUSTMENT OF THE THICKNESS PROFILE IN THE PRODUCTION OF BLOWN FILMS

摘要

A device arranged in the cooling ring of an apparatus for the production of blown films in order to adjust the thickness profile thereof comprises a plurality of equally spaced motor-driven actuators (5) that adjust the flow rate of the flow of a cooling fluid directed towards a forming cone (2), as well as a plurality of equally spaced resistances (11) provided with finned dissipators (12) arranged in the path of the cooling flow. In this way, the device combines the characteristics of low power consumption and high adjustment velocity of a volumetric device with the higher angular resolution achievable through the heating elements of a thermal device, and all of this with an operating method that prevents the risks of bubble instability or adhesion, achieves a high energy efficiency and guarantees a wide thickness adjustment range.