Backventilsystem för luft- eller vätskefyllbara behållare samt förfarande att bilda backventilsystem

摘要

The present invention relates to a non return valve which is provided by welding two lines in two flat upon each other lying film surfaces, which are then folded towards each other and after that they are joined together around the outer edges except the opening channel so that over pressure is formed when the container is filled completely or partly and then the non return valve starts to operate with safe sealing. The opening channel is formed between two against each other lying sections of film material, which sections extend from the outside of the container into it and are joined together right up to the opening channel.