Blown film extrusion plant

Abstract

In a blown film extrusion plant comprising a blow head and an air cooling ring, between the blow head and the air cooling ring at least one cooling device should be provided.

1 . Blown film extrusion plant comprising a blow head and an air cooling ring, wherein at least one cooling device is provided between the blow head and the air cooling ring. 
   
   
       2 . Blown film extrusion plant according to  claim 1 , wherein the cooling device is configured as a precooling ring and is inserted between the blow head and the air cooling ring. 
   
   
       3 . Blown film extrusion plant according to  claim 2 , wherein a film bubble within the precooling ring is passed coaxially and cooled by contact cooling. 
   
   
       4 . Blown film extrusion plant according to  claims 3 , wherein the precooling ring is cooled with a cooling medium in order to cool the film bubble. 
   
   
       5 . Blown film extrusion plant according to  claim 4 , wherein the film bubble, following exit from the blow head, comes to bear internally against a contact surface of the cooling device. 
   
   
       6 . Blown film extrusion plant according to  claim 5 , wherein the contact surface of the cooling device is of rotationally symmetric and cylindrical or conical configuration. 
   
   
       7 . Blown film extrusion plant according to  claim 5 , wherein the contact surface of the cooling device is configured as a microporous shell surface from which gaseous and/or liquid cooling medium enters into contact with the outer shell surface of the film bubble. 
   
   
       8 . Blown film extrusion plant according to  claim 1 , wherein the cooling device has at least one inlet and at least one outlet, which supply a duct or a plurality of ducts with liquid or gaseous medium. 
   
   
       9 . Method for producing a film bubble by means of a blown film extrusion plant in which the film bubble is extruded from a blow head and is subsequently cooled in an air cooling ring, characterized in that, between the blow head and the air cooling ring, an additional cooling of an outer shell surface of the film bubble is realized by means of a cooling device. 
   
   
       10 . Method according to  claim 9 , wherein the film bubble, following exit from the blow head is cooled by means of a cooling device, so that the stretching in the hose-forming zone occurs at a low temperature. 
   
   
       11 . Method according to  claim 10 , including providing a strong additional cooling in the production process of a film bubble, between the blow head and the air cooling ring, a higher degree of orientation and hence additionally improved strength properties, as well as an increase in mass output, are obtained, a cooling temperature of the film bubble being adjustably and controllably altered, during operation, via the cooling device. 
   
   
       12 . Method according to  claim 9 , wherein the film bubble, directly following exit from the blow head, is adjustably cooled by means of the cooling device, with cooling of a cylindrical contact surface or by direct action of a liquid and/or gaseous medium upon the outer shell surface of the film bubble, rapidly to a lower temperature in order to increase the strength property and raise the mass output during operation.