Laboratory funnels are

funnels A funnel is a tube or pipe that is wide at the top and narrow at the bottom, used for guiding liquid or powder into a small opening. Funnels are usually made of stainless steel, aluminium, glass, or plastic. The material used in its construc ...

that have been made for use in the chemical laboratory. There are many different kinds of funnels that have been adapted for these specialized applications.

Filter funnel A filter funnel is a laboratory funnel used for separating solids from liquids via the laboratory process of filtering. In order to achieve this, a cone-like shaped piece of filter paper is usually folded into a cone and placed within the funnel. ...

thistle funnel A thistle tube is a piece of laboratory glassware consisting of a shaft of tube, with a reservoir and funnel-like section at the top. Thistle tubes are typically used by chemists to add liquid to an existing system or apparatus. Thistle funnels a ...

s (shaped like

thistle Thistle is the common name of a group of flowering plants characterised by leaves with sharp prickles on the margins, mostly in the family Asteraceae. Prickles can also occur all over the planton the stem and on the flat parts of the leaves. ...

flowers), and dropping funnels have stopcocks which allow the fluids to be added to a flask slowly. For solids, a powder funnel with a short and wide neck/stem is more appropriate as it prevents clogging. When used with filter paper, filter funnels,

Buchner Buchner is a German surname. Notable people with this surname include the following: * Andreas Buchner (1776–1854), German historian * Annemarie Buchner (1924-2014), German Olympian * August Buchner (1591–1661), German influential Baroque po ...

and

Hirsch funnel Hirsch may refer to: Places * Hirsch, Saskatchewan, Canada * Hirsch Observatory, in Troy, New York, U.S. People * Afua Hirsch (born 1981), Norwegian-born British writer, broadcaster, and former barrister * Alex Hirsch (born 1985), American anim ...

s can be used to remove fine particles from a liquid in a process called

filtration Filtration is a physical separation process that separates solid matter and fluid from a mixture using a ''filter medium'' that has a complex structure through which only the fluid can pass. Solid particles that cannot pass through the filter ...

. For more demanding applications, the filter paper in the latter two may be replaced with a

sintered Clinker nodules produced by sintering Sintering or frittage is the process of compacting and forming a solid mass of material by pressure or heat without melting it to the point of liquefaction. Sintering happens as part of a manufacturing ...

glass frit. Separatory funnels are used in liquid-liquid extractions.

Manufacturing

Borosilicate glass is one of the most common materials of choice for laboratory applications due to its inertness compared with metals or plastics. However, plastic funnels made of non-reactive

polyethylene Polyethylene or polythene (abbreviated PE; IUPAC name polyethene or poly(methylene)) is the most commonly produced plastic. It is a polymer, primarily used for packaging ( plastic bags, plastic films, geomembranes and containers including bo ...

are used for transferring aqueous solutions. Plastic is most often used for powder funnels which do not come into contact with solvents in normal use.

The types of funnels in the laboratory

* Plain funnels exist in various dimensions, with longer or shorter necks. *

s have a neck of a thin capillary tube and ribs which increase the filter-papers' effectiveness and thus accelerate the process of filtering. * Powder funnels have a short and wide neck for fast pouring of powders. * Separatory funnels are pear-shaped, have a cap and a short neck, with a stopcock for the even pouring of fluids. These are used to decant two immiscible fluids. It can be graduated, though this is not very common. *

s are shaped much like normal funnels, but contain holes or sintered glass at the base for quick filtrations. * Dropping funnels are a cylindrical, regularly graduated funnel with standard taper

ground glass joints Ground glass joints are used in laboratories to quickly and easily fit leak-tight apparatus together from interchangeable commonly available parts. For example, a round bottom flask, Liebig condenser, and oil bubbler with ground glass joints may ...

. These are often supplied with a pressure equalizer. *

Buchner funnel Buchner is a German surname. Notable people with this surname include the following: * Andreas Buchner (1776–1854), German historian * Annemarie Buchner (1924-2014), German Olympian * August Buchner (1591–1661), German influential Baroque poet ...

s are made of porcelain and include a plate of sintered glass or perforated porcelain. These are used in filtration under low pressure with a Buchner flask. * Hot filtration funnel is a less commonly seen funnel where the funnel is jacketed, and surrounded by a heated fluid. *

Eco funnel The ECO Funnel, also known as the "Safety Ecological Funnel", is a funnel intended to be affixed to a receptacle for liquid chemical waste. It is designed to reduce environmental contamination, in compliance with OSHA and EPA mandated safety proto ...

is equipped with a latching lid and gasket to reduce chemical contamination and conform to OSHA and EPA regulations.

References

{{Laboratory equipment Laboratory glassware