Valve sack for bulk material

摘要

Valve sack for bulk material, composed of a tubular jacket (10) made of paper, film or the like, having at both ends of the sack sack floors (12), which are formed by gluing together or similar processes, and a filling valve tube (14), the outer section (14a) of which is glued to the sack floor (12) in the region of one of the corner folds (16) of the said sack floor (12) and the inner section (14b) of which projects loosely into the sack and can be sealed off, when the sack has been filled, by folding along a folding line (18), and of a sealing tube (20) which is composed of an outer section (20a) which is open at its end, is accessible from outside and is glued to the sack floor (12) and of an inner section (20b) which is sealed off at its end and is glued to that surface of the filling valve tube (14) which points towards the sack floor (12) when the filling valve tube (14) is stretched, the sealing tube (20) being folded, when the filling valve tube (14) is stretched, in the region of the folding line (18) and, during stretching, by the introduction of air into the open end of the outer section (20a), folding the filling valve tube (14) about the folding line (18) so as to seal it. <IMAGE>