- Filter flasks are heavy-walled to provide the mechanical strength needed for vacuum filtration.
- DURAN® filtering flasks are available in two shapes, Erlenmeyer and cylindrical bottles.
- All DWK vacuum filter flasks are manufactured from borosilicate glass.
- DURAN® filter flasks are ideal for separation applications, including strong acids or bases
Filter Flasks
Frequently Asked Questions
To perform vacuum filtration, you will need the following:
-
Vacuum filter flask
-
Büchner funnel or Gooch crucible
-
Filter paper or filter membrane
-
Rubber stopper with hole
-
Vacuum pump
-
Clamp
A Büchner funnel is usually used for vacuum filtrations. These can be made from porcelain or borosilicate glass. A Büchner funnel has a standard cylindrical shape and has a fixed perforated or fritted (sintered) glass filter plate.
Heavy-walled tubing is used with a vacuum filter flask to prevent the collapse of the filtration system under vacuum and to facilitate fast filtration.
Use a rubber stopper with a hole that is large enough to accommodate the stem of the Büchner funnel to fit into the neck of the filter flask. The rubber stopper seals the filter flask, preventing air from entering during filtration. Since a vacuum filter flask is a collection reservoir to keep the filtered liquid, a clamp can be used to prevent the flask from moving when under vacuum.
Not necessarily, it will depend on the type of Büchner funnel you are using. Glass Büchner funnels, that have a fixed fritted (sintered) filter disc, are available in different filter porosities (grades) that can be used without the need to use filter paper or a filter membrane. Büchner funnels that have a perforated plate will require the use of filter paper or a filter membrane to retain the solid particles in the funnel during filtration.