A Büchner flask, also known as a vacuum flask,The use of the term ''vacuum flask'' sometimes causes confusion with the Thermos flask filter flask, suction flask, side-arm flask, Kitasato flask or Bunsen flask, is a thick-walled

Erlenmeyer flask An Erlenmeyer flask, also known as a conical flask (British English) or a titration flask, is a type of laboratory flask which features a flat bottom, a conical body, and a cylindrical neck. It is named after the German chemist Emil Erlenmeyer ...

with a short glass tube and

hose barb Hose barbs are cylindrical pieces or parts for attaching and securing of hoses (tubing). The barb-like rings on the cylindrical piece allow for an easy push-connection of flexible-plastic or rubber tubing that is not so easily disconnected. Hose ...

protruding about an inch from its neck. The short tube and hose barb effectively act as an adapter over which the end of a thick-walled flexible hose (tubing) can be fitted to form a connection to the flask. The other end of the hose can be connected to source of

vacuum A vacuum is a space devoid of matter. The word is derived from the Latin adjective ''vacuus'' for "vacant" or "void". An approximation to such vacuum is a region with a gaseous pressure much less than atmospheric pressure. Physicists often dis ...

such as an aspirator,

vacuum pump A vacuum pump is a device that draws gas molecules from a sealed volume in order to leave behind a partial vacuum. The job of a vacuum pump is to generate a relative vacuum within a capacity. The first vacuum pump was invented in 1650 by Otto v ...

, or house vacuum. Preferably this is done through a trap (see below), which is designed to prevent the sucking back of water from the aspirator into the Büchner flask. The purpose of applying a vacuum is to speed the filtration by providing a pressure differential across the filter medium that is greater than that produced by gravity alone. The thick wall of the Büchner flask provides it the strength to withstand the pressure difference while holding a vacuum inside. It is primarily used together with a

Büchner funnel A Büchner funnel is a piece of laboratory equipment used in filtration. It is traditionally made of porcelain, but glass and plastic funnels are also available. On top of the funnel-shaped part there is a cylinder with a fritted glass disc/per ...

fitted through a drilled rubber bung or an elastomer adapter (a Büchner ring) at the neck on top of the flask for the

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 ...

of samples. The Büchner funnel holds the sample isolated from the suction by a layer of

filter paper Filter paper is a semi-permeable paper barrier placed perpendicular to a liquid or air flow. It is used to separate fine solid particles from liquids or gases. The raw materials are different paper pulps. The pulp may be made from softwood, hardwo ...

. During filtration, the filtrate enters and is held by the flask while the residue remains on the filter paper in the funnel. The Büchner flask can also be used as a vacuum trap in a vacuum line to ensure that no fluids are carried over from the aspirator or vacuum pump (or other vacuum source) to the evacuated apparatus or vice versa. It is commonly thought to be named after the Nobel Laureate

Eduard Buchner Eduard Buchner (; 20 May 1860 – 13 August 1917) was a German chemist and zymologist, awarded the 1907 Nobel Prize in Chemistry for his work on fermentation. Biography Early years Buchner was born in Munich to a physician and Doctor Extraor ...

, but it is actually named after the industrial chemist

Ernst Büchner Ernst Wilhelm Büchner (18 March 1850 – 25 April 1924) was the German industrial chemist after whom the Büchner flask and Büchner funnel are named. The patent for his two inventions was published in 1888. Life His father was the pharmacist ...

. It is also known as a Kitasato flask in honor of

Kitasato Shibasaburō Baron was a Japanese physician and bacteriologist. He is remembered as the co-discoverer of the infectious agent of bubonic plague in Hong Kong during an outbreak in 1894, almost simultaneously with Alexandre Yersin. Kitasato was nominated ...

Notes

References

* {{DEFAULTSORT:Buchner Flask Laboratory glassware Air-free techniques