| 摘要 |
A self-closing valve assembly for installation in a dispensing opening of a container, a seal cap or the like, includes a first closure element having a domed wall portion of resilient material incorporating a passage-opening, said wall portion being resiliently deformable from a closed position into an open position under the influence of a first differential pressure force resulting from pressures acting on its opposite surfaces, and a second closure element having a domed wall portion for sealing the passage-opening when the first closure element is in its closed position. In order to balance the pressure prvailing in a container provided with the valve assembly when a pressure-increasing squeezing force is no longer exerted on the container, the second closure element is adapted to be brought out of its sealing relationship with the passage-opening in the first closure element under the influence of a second differential pressure force resulting from pressures acting on its opposite surfaces, said second differential pressure force being directed oppositely to said first differential pressure force.
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