Funnel

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For other uses of the term, see funnel (disambiguation).

A typical kitchen funnel.

A funnel is a pipe with a wide, often conical mouth and a narrow stem. It is used to channel liquid or fine-grained substances into containers with a small opening. Without a funnel, much spillage will occur.

Funnels are usually made of stainless steel, glass, or plastic. The material used in its construction should be sturdy enough to withstand the weight of the substance being transferred, and it should not react with the substance. For this reason, stainless steel or glass are useful in transferring diesel, while plastic funnels are useful in the kitchen. Sometimes disposable paper funnels are used in cases where it would be difficult to adequately clean the funnel afterwards (for example, in adding motor oil to a car). Dropper funnels, also called dropping funnels or tap funnels, have a tap to allow the controlled release of a liquid.

The term "funnel" is sometimes used to refer to the chimney or smokestack on a steam locomotive or a ship. There is also a type of spider known as a funnel-web due to its habit of building its web in the shape of a funnel.

1 Laboratory funnels
- 1.1 Construction
2 See also
3 External links

[edit] Laboratory funnels

There are many different kinds of funnels that have been adapted for specialized applications in the laboratory. Filter funnels, thistle funnels (shaped like thistle flowers), and dropping funnels have stopcocks which allow the fluids to be added to a flask slowly. For solids, a powder funnel with a wide and short stem is more appropriate as it does not clog easily.

When used with filter paper, filter funnels, Buchner and Hirsch funnels can be used to remove fine particles from a liquid in a process called filtration. For more demanding applications, the filter paper in the latter two may be replaced with a sintered glass frit.

Separatory funnels are used in liquid-liquid extractions.

[edit] Construction

Glass is the material of choice for laboratory applications due to its inertness compared with metals or plastics. However, plastic funnels made of unreactive polyethylene are used for transferring aqueous solutions. Plastic is most often used for powder funnels which do not come into contact with solvent in normal use.