| 摘要 |
A bag and the apparatus and method for forming the bag, the bag being formed using a web 256 of packaging material featuring one or more longitudinal folds 284, spaced apart transversely across the web, which are stiffened by joining together laterally spaced portions of the fold and forming the web into a tube. The bag may be closed at one end region by a transversely extending seal and can have a plurality of sides. The folds may have reinforcing elements attached to them, disposed between the laterally spaced portions. The reinforcing folds may be disposed inwardly of the external surface of the tube. The reinforcing portion may be joined to an inner surface of the bag. The fold forming means may comprise elongate elements 292 which act with a surface defining convex depressions, to define ridges on a surface of the web. The folds may have a generally V-shaped cross-section. The laterally spaced portions of the folds may be joined together by heat-sealing and the heat may be applied directly to the surface portions of the web which are to be joined. The heat sealing may be achieved using a stream of hot gas directed between the laterally spaced portions which may then be pressed together to form the reinforcing folds. |
