| 摘要 |
A container or bottle closure in the form of a one-piece cap. The cap is formed with a flat top and a depending skirt having means for attachment to the container neck such as internal threads which mate with complementary threads on the container. An annular flange depends downwardly from the cap top to act as a sealing between the closure and the container. A vent is provided through the cap top to equalize the container pressure to atmospheric pressure. The vent takes the form of a plurality of orifices created by a laser beam which produces a hole of a diameter of 0.003 inches or less. Gas may flow equally well from the inside of the container outwardly or from the outside of the container inwardly, depending upon the pressure difference. The orifice diameter is sufficiently small to prevent the flow of a liquid product through the holes under the same pressure difference.
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