| 摘要 |
A burette top vent which resists air blockage includes a peripherally skirted cap having a generally planar circular base transfixed by a short integral tube having an upper portion to which tubing from a source of fluid may be attached and a lower portion from which fluid can drip into the burette. The base is perforated by an array of arcuate slots that permit air to enter the burette, and the bottom surface of the base has a shallow annular relief intersecting the slots. A ring-shaped hydrophobic filter disk hermetically affixed beneath the relief. The relief prevents the filter disk from lying flush against the bottom surface of the base.
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