Bunsen burner
The Bunsen burner is a small gas burner in which the combustion gas partially sucks in the combustion air itself based on the principle of a jet pump .
In addition to the Teclub burner, the Bunsen burner is often used in the chemical laboratory to heat material samples or liquids. The Bunsen burner is named after Robert Wilhelm Bunsen (1811–1899); the original invention, however, comes from Michael Faraday and was decisively improved by Peter Desaga , Bunsen's laboratory assistant, in 1855 in Heidelberg .
Structure and functionality
The laboratory gas burner consists of an approximately 15 cm long piece of pipe in which the gas flows upwards and sucks in the combustion air itself through adjustable openings based on the principle of a jet pump . With modern burners, a grille or fine bores at the top of the burner prevent the flame from flashing back into the burner. The burner is mostly operated with propane , butane or town / natural gas.
The burner stands on a heavy base on which the fuel gas supply is also attached. A tube that resembles a small chimney is arranged perpendicular to it. The fuel gas passes an opening through which an oxidizer , usually air , is sucked in. The opening is adjustable in its width. At the top of the tube, the gas is ignited and burned. When the air supply is open, the oxidizer and fuel gas mix within the Bunsen burner. The flame then burns as a blue and hot premixed flame . When the opening is closed, the fuel gas only mixes with the oxidizer at the top of the tube and develops a lower temperature . Such a diffusion flame , also known as a luminous flame, is cooler at up to 900 ° C and appears yellow. Intermediate forms of the flame are called partial premix flames . The flame temperature can be regulated between 350 and approx. 1000 ° C ( Teclub burner 1300 ° C). The flame is divided into a core, jacket and the almost invisible flame edge. In the core there is a temperature of around 250–550 ° C, the jacket (depending on the source between 1000 ° C and 1200 ° C) and edge (around 900 ° C) are, on the other hand, significantly hotter, but less easy to see because the gas is here burns almost completely. The cones that form with a premixed flame and, to a lesser extent, also with a partial premixed flame, are divided into oxidizing flame (outside) and reducing flame (inside), with the highest temperatures at their transition.
The Bunsen burner distinguishes between two different types of flame, the diffusion flame and the premixed flame .
application
Bunsen burners are mainly used for preliminary tests in analytical chemistry, for example soldering tube samples , borax or phosphorus beads and flame coloration . When the air supply is fully open, it can also be ensured that a sterile environment is created around the flame. Thus it is possible to carry out sterile work in the vicinity of the flame, such as. B. in microbiology . Bunsen burners are also used in molecular cuisine to heat various dishes. Even the simplest glass work can be carried out with a Bunsen burner, for example the round melting of cut glass tubes and glass rods or the loosening of cuts .
Web links
Individual evidence
- ↑ NUGI: Overview of the common laboratory equipment
- ↑ Heike Frerichs: Chemical experiments from everyday life, experiments with simple means . 5th edition. Persen im Aap Lehrerfachverlag, 2018, ISBN 978-3-8344-3378-7 ( limited preview in Google book search).
- ↑ Seilnacht: heating