FLAT FILM DIE WITH ADJUSTABLE OPERATING POINT

摘要

What is disclosed is an adjustable wide-slit extrusion nozzle containing a distributor channel having a straight exit edge and a cross-section taken from the supply port for the nozzle to one end thereof which corresponds to the equation: Ri=Ro(b/B)1/3, wherein: B is the width of the distributor channel from the supply port to one end of the channel; b is a width coordinate measured from one end of the distributor channel; Ro is the hydraulic radius of the distributor channel at the supply port; and Ri is the hydraulic radius of the distributor channel at the distance b from the channel end. At least one choker bar insert is placed between the distributor channel and the nozzle mouth; the choker bar has a damming area surface whose length dimensions Li in the direction of flow at distances b from the channel end correspond to the equation Li=Lo(b/B )2/3, wherein Lo is the length of the damming strip at the supply port; Li is the length in flow direction of the damming area at the selected distance b from the channel end; and b and B are defined as above. The damming area rises above the remaining surface area of the insert, before or behind the damming area surface, in a uniform jump H, of from 0.1 to 5 times the exit height H3 of the nozzle and is a height-adjustable parallel faced mounted in the nozzle.