| 摘要 |
In a conventional airtight bag formed in a double layer of an inner sealing bag made of soft plastic film with a flat cylindrical check valve body mounted in it as a filling and discharging port and an outer tough sheath coating and protecting the inner bag, the valve body mounted on the inner bag projects through an opening provided in the sheath. The function of protecting the inner bag is lowered at this part, which cannot endure the internal pressure when it increases beyond a predetermined limit, with the resultant breakage of the inner bag. This drawback can be overcome by eleiminating the opening at the sheath. This invention contemplates to provide a pressure-resistant sealed bag in which a sewed seal (6) is provided at the sides of the sheath (2) together with the valve body in the state that a flat cylindrical valve body (3) projects and a passage (10) for filling and exhausting it is provided through the sewed line (7), thereby increasing its performance to endure an internal pressure rise while maintaining its orginal function. This bag particularly exhibits high reliability as airdunnage for freight transportation. |
