Cross section of a Büchner Flask. Note the hose barb pointing right for attaching a vacuum source.

A Büchner funnel is attached to the flask via a black elastomer adapter. The hose barb is connected via vacuum hose to a vacuum source such as an aspirator. An aspirator, also called an Eductor-jet pump or filter pump is a device that produces Vacuum by means of the Venturi effect. The flask should be clamped before use or the hose will likely cause it to tip.

A Büchner flask, also known as a vacuum flask^[1], filter flask, side-arm flask or Kitasato flask, is a thick-walled Erlenmeyer flask with a short glass tube and hose barb protruding about an inch from its neck. An Erlenmeyer flask, commonly known as a conical flask or E-flask, is a widely used type of Laboratory flask which features a conical base and a cylindrical The short tube and hose barb effectively acts 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 such as an aspirator, vacuum pump, or house vacuum. This vacuum means "absence of matter" or "an empty area or space" for the cleaning appliance see Vacuum cleaner. An aspirator, also called an Eductor-jet pump or filter pump is a device that produces Vacuum by means of the Venturi effect. A vacuum pump is a device that removes gas molecules from a sealed volume in order to leave behind a partial Vacuum. Preferably this is done through a trap (see below), which is designed to prevent the suckback of water from the aspirator into the Büchner flask.

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 fitted through a drilled rubber bung or an elastomer adapter at the neck on top of the flask for filtration of samples. A Büchner funnel is a piece of Laboratory equipment used in Suction filtration. Filtration is a mechanical or physical operation which is used for the separation of solids from fluids (liquids or gases by interposing a medium to fluid flow through which the fluid 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 flow 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 for the Nobel Laureate, Eduard Buchner, but it is actually named for the industrial chemist Ernst Büchner. Eduard Buchner (May 20 1860 &ndash August 13 1917 was a German chemist and zymologist, the winner of the 1907 Nobel Prize in Chemistry Also known as a Kitasato flask, in honor of Shibasaburo Kitasato

See also

• Büchner Bong

References and notes

1. ^ The use of the term vacuum flask sometimes causes confusion with the Thermos flask

• Jensen, William B. was a Japanese Physician and bacteriologist. He is remembered as the co-discoverer of the infectious agent of Bubonic plague in Hong Kong in (September 2006). "The Origins of the Hirsch and Büchner Vacuum Filtration Funnels" (PDF). Journal of Chemical Education 83 (9): 1283. The Journal of Chemical Education ( JCE) is a monthly subscription-only periodical available in both print and electronic versions