APPARATUS AND METHOD FOR PROVIDING UNIAXIAL CHANGES IN THE LENGTH OF FILM SHEETS Russian patent published in 2022 - IPC B29C49/00 B29C55/06 B29C55/28 

FIELD: shaping.

SUBSTANCE: group of inventions relates to an apparatus and method for providing uniaxial changes in the length of film sheets in the machine direction, and to a line for producing film by extrusion blowing for production of tubular film using the apparatus. Apparatus comprises: a manufacturing clearance defined by two rolls, used to direct the film sheet in the machine direction. The first roll in the direction of film transportation is therein characterised by a first peripheral speed, and the second roll in the direction of film transportation is characterised by a second peripheral speed. At least one of the rolls therein constitutes an air flow roll, by means whereof air enters from the outside, wherein a negative pressure source is connected to the roll for the air flow, and, therefore, negative pressure is applied to the roll, and at least one of the air flow rolls constitutes a combination of an air flow roll and a heat treatment roll.

EFFECT: manufacture of a film sheet with improved flatness, wherein transverse neck formation and, therefore, edge thickening are reduced, allowing for an improvement in the final film roll quality.

14 cl, 2 dwg