| 摘要 |
A separatory funnel having a valve stem mounted through its center to accurately open, close, and regulate the flow of liquid from the funnel. The valve stem is provided with a passageway therein for forming a separate channel from the path of liquid flow to permit air to pass through the separatory funnel independently of the liquid flow from the funnel. This air passageway may exit internally of the funnel chamber, or externally thereof. In the external exit version, the valve stem is modified so that the air exit path can be capped and/or connected to another device. The lower end of the valve stem is provided with sealing structure of several types for assuring a tight and positive seal when the valve is closed. Also, the lower end of the valve stem is sandblasted to effect flow of all liquid therealong and tapered to a spherical ball at the very end for collecting and forming liquid droplets for precision liquid flow measurement. Another embodiment eliminates the roughened surface, but provides an insert bushing for both sealing the liquid flow as well as assuring the flow of the liquid to the very tip of the valve stem. Graduated markings can be provided on either the external surface of the funnel chamber or the external surface of the valve stem. Indicia may also be provided on the adjusting knob for the valve stem to permit accurate liquid flow control and repeatability of adjustment thereof.
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