A method for the production of which is provided with ventilsaecken

摘要

A web of bag-making material has longitudinally folded rectangular sheets adhered at intervals to one face by one flap before longitudinal margins of the web are folded over, stuck to the other flap of each sheet and joined where they overlap to define a tube, whereafter sections are severed from the tube to make bags to be formed with cross-bottom closures at the ends. The size and position of each folded sheet is such that it will subsequently form an internal seal for the respective cross-bottom closure but the sheet for the closure at one end is made as two longitudinally aligned segments of which one segment has been transversely pre-folded back onto itself to define a tab adjacent the edge of the other segment with the length of a subsequent filling valve for the bag. Following formation of the cross-bottom closures, the filling valve is formed by unfolding the pre-folded tab.