Funnels and Filtration
Funnels and filtration products are familiar items in the laboratory used for filtering, filling, decanting or transferring liquids or powders from one vessel to another. Laboratory funnels are made from glass, plastic (typically HDPE) or occasionally metal. Glass funnels are reusable, autoclavable and generally more heat-resistant, chemical-resistant and more durable than plastic funnels, although they may be prone to increased risk of breakage. Glass funnels can be made from soda-lime glass for general purpose work, or from borosilicate glass for more exacting applications.
What are the different types of funnels?
- General purpose filling funnels for channelling, filling and decanting liquids
- Short stem funnels or powder funnels, used to prevent the stem from clogging when funnelling fine particulates
- Long stem analytical funnels, often used with filter papers
- Funnels with specially fluted interiors for rapid filtration
- Glass Büchner funnels, glass filtering funnels or vacuum filtration funnels, made with an integral sintered glass disc for filtering precipitates or particulates without the need for filter papers. The sintered discs come in a range of pore sizes
- Bottle-tops and filter units, or complete filtration assemblies complete with a receiving vessel
- Pear-shaped or cylindrical separatory funnels (separating funnels) fitted with a stopper and a PTFE or glass stopcock, used in the chemistry laboratory for pouring off layered immiscible liquids
- Weighing funnels or other special purpose funnels
Most types of funnels are manufactured in a range of sizes and dimensions, such as varying top diameters, stem lengths, stem diameters, bowl angles, bowl capacities and overall lengths.