Additional highlights:
- Cylindrical wall – to prevent over-filling
- Fritted bottom – for even, smooth filtering
- Useful for collecting precipitated crystals from a solution
Construction:
Each Buchner Funnel is a solid, cylindrical construction with a large, fritted (or perforated) top opening consisting of many tiny holes. The porcelain chamber narrows to a tube-shaped hole on the bottom, through which liquids can pass.
The narrow bottom portion of the funnel can be placed through a rubber stopper to create an air-tight seal, forcing both liquids and gases to pass through the numerous tiny holes at the top.
The liquid drains into a Buchner Flask (or filter flask). The receiving flask has a vacuum attachment, to which vacuum tubing can be connected.
By placing qualitative filter paper on top of the perforations, you can effectively filter substances by means of vacuum filtration.
The key benefit of using this style of filtration is that the liquid moves through the funnel much faster than with the force of gravity alone (several orders of magnitude, in fact).