| 摘要 |
A valved vent for a liquid drainage system comprising, a receptacle having a chamber to receive liquid, and a filter pervious to air and substantially impervious to the passage of bacteria, with the filter communicating with the atmosphere. The vent has a valve communicating between an upper portion of the chamber and the filter. The valve may be selectively opened to permit passage of air between the atmosphere and the chamber through the filter, and may be selectively closed to prevent passage of liquid from the chamber against the filter.
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