Device for the wrinkle-free flattening and cooling of a seamless thermoplastic foil tube

Claim 1

AN EXTRUSION APPARATUS FOR FORMING FLATTENED THERMOPLASTIC FOIL TUBING, COMPRISING: EXTRUSION MEANS INCLUDING AN EXTRUSION HEAD FOR FORMING UNFLATTENED THERMOPLASTIC FOIL TUBING; INFLATING MEANS FOR INFLATING THE NEWLY EXTRUDED TUBING WITH AN INFLATING FLUID UNDER SUPERAMBIENT PRESSURE; A PAIR OF CLOSELY SPACE SQUEEZE ROLLS MOUNTED FOR ROTATION ABOUT PARALLEL AXES SPACED FROM SAID EXTRUSION HEAD, SAID TUBING PASSING BETWEEN SAID SQUEEZE ROLLS, AND SAID SQUEEZE ROLLS FORCING THE OPPOSITE WALLS OF SAID TUBING INTO CONTACT AND THERBY SUBSTANTIALLY IMPEDING THE ESCAPE OF SAID INFLATING FLUID FROM WITRHIN SAID NEWLY EXTRUDED TUBING; A PAIR OF MAIN GUIDING AND COOLING PLATES HAVING CLOSELY SPACED EDGES ADJACENT SAID ROLLS, SAID TUBING PASSING BETWEEN SAID CLOSELY SPACED EDGES JUST PRIOR TO PASSING BETWEEN SAID ROLLS, AND CONTACTING SAID MAIN PLATES OVER COOLING AREAS EXTENDING SUBSTANTIALLY TO THE MAXIMUM DIAMETER OF THE UNFLATTENED TUBING; COOLING MEANS FOR COOLING SAID MAIN PLATES BY CIRCULATION OF A COOLING FLUID IN HEAT EXCHANGING RELATIONSHIP THEREWITH; AUXILIARY COOLING PLATES CONTACTING SUBSTANTIAL AREAS OF SAID TUBING, SAID MAIN AND AUXILIARY COOLING PLATES BEING OF SUCH CONFIGURATION THAT SAID TUBING IS CUMULATIVELY SUBJECTED TO SUBSTANTIALLY UNIFORM COOLING THROUGHOUT ITS CIRCUMFERENCE DURING ITS PAS SAGE FROM SAID EXTRUDING HEAD TO SAID ROLLS; AND COOLING MEANS FOR COOLING SAID AUXILIARY COOLING PLATES BY CIRCULATION OF A COOLING FLUID IN HEAT EXCHANGING RELATIONSHIP THEREWITH.