Stitched valve bag and procedure for making same.

摘要

The invention concerns a stitched valve bag and a procedure for manufacturing stitched valve bags from a material web run in tubular form. The valve bag (30) is provided at both ends with a stitched seam (38), and the bag (30) has in one corner a valve member (34') constituting a valve opening. In the longitudinal direction of the mantle part (31) of the bag (30) has at one end (32) at a distance from the corner of the bag been made an incision (36) longitudinal to the mantle (31). The portion between the incision (36) and the corner has been folded to become a valve member (34'), along a folding line (35) extending substantially from the bottom of the incision (36) obliquely to the margin of the mantle part (31). On the side beyond the incision (36) the bag end (32) has for improved strength been folded double before stitching said end of the bag.