In order to store liquid in a foil bag with no risk that liquid leaks from the bag, the bag is provided with a valve in the inlet channel (5). The valve consists of two valve flaps (8) formed by the foil by folding and at their sides being welded together in a weld seam (2) for the formation of the channel...http://www.google.es/patents/US4822180?utm_source=gb-gplus-sharePatente US4822180 - Foil bag
