Wash bottle

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Wash bottle
Use of a gas washing bottle with frit

The washing bottle (impinger) or gas washing bottle is a laboratory device that is switched into a gas flow, whereby the gas is forced by means of a dip tube to bubble through a liquid before it leaves the container again. It is used to clean gases ("wash"). The bottle is filled with a solvent into which the gas supply tube is immersed. The directly introduced bubbling gases are partially or completely freed from impurities because they remain in the solvent. The washed gases can then be drawn off again through a second tube at the top of the vessel. The first gas washing bottle for collecting airborne dust was developed in 1922.

In the simplest case, the gas can actually be introduced into the liquid through a glass tube, but alternatively perforated nozzle plates or frits made from a wide variety of materials are used. In this way, the smallest possible gas bubbles should be generated, so that a large contact surface between gas and liquid is created. The main material used in the laboratory is glass - preferably transparent - but there are also bottles made of chemically resistant plastics and in rare cases even made of metal.

application areas

The main purpose is an intimate contact of the gas with the scrubbing liquid, which does not have to be just water. On the contrary: By using different liquids, a wide range of tasks can be fulfilled.

The following applications can be carried out for the gas flow:

  • Solids (e.g. dust , smoke ) can be removed with water . Humidification takes place at the same time.
  • Acid traces can be removed by using alkalis .
  • Due to its hygroscopic properties, highly concentrated sulfuric acid is used to remove water vapor .
  • Using various solvents , certain components can be removed from the gas in a targeted manner.
  • Analogous to the humidification, it can also be desirable to enrich the gas stream with vapor of the scrubbing liquid.
  • The rising bubbles can also serve as a visual control for an existing gas flow.
  • The submerged pipe can prevent gas from flowing back in the opposite direction, although no unwanted pressure can build up in the direction of flow (like a fermentation seal in wine production ).
  • Detection of carbon dioxide : Kalkwasser becomes cloudy when carbon dioxide is passed through it.
  • Detection of bioaerosols : Airborne bacteria are deposited in a physiological saline solution.

The following applications exist for liquids:

  • If the liquid consists of more than one substance, one (several) components can be removed - stripped - out. In this case, the aim is not to purify the gas, but rather the liquid.

safety

In the event of a reversal of the gas flow, e.g. due to a pump failure, the end of the gas-generating process, the drying up of a pressurized gas cylinder and cooling with contraction of the gas volume upstream, it may be necessary to ensure that the scrubbing liquids are not sucked back upstream of the gas. This can be done by connecting a reversely oriented gas washing bottle, which in this case takes up the liquid, or by a large-volume cavity above the immersion tube. In this case, the washing bottle may only be filled with as much washing liquid as this cavity can safely accommodate (bubbling back).

Other uses

Devices that are used for inhalative consumption of tobacco smoke , such as the shisha or a bong , are both water pipes, based on the washing bottle principle .

In power plants, the principle of the washing bottle is used in gas washers to remove pollutants from the flue gas.

The principle of the wash bottle is used when measuring air pollution. Ambient air is passed through a gas washing bottle filled with distilled water. Changes (conductor reaction) in the electrical water resistance can then be evaluated electronically.

Smaller versions - called bubblers, bubblers or bubble counters - serve as indicators or control displays that a gas flow is flowing in a pipe or that there is a certain, oriented pressure difference between two rooms. Application similar to a flow indicator in liquid flows. The number of bubbles rising in the bubble counter per unit of time, e.g. B. bubbles per minute, can serve as a semi-quantitative display for the amount of gas flowing. In combination with a needle valve , the experimenter can thus carry out an approximate regulation of the gas volume flow.

literature

  • DIN 12463: 1967-03 Laboratory glassware; Bottles 200 mm high with standard ground joint . Beuth Verlag, Berlin.
  • DIN 12596: 1984-01 Laboratory glassware; Gas washing bottles; Drechsel shape . Beuth Verlag, Berlin.

Web links

Wiktionary: wash bottle  - explanations of meanings, word origins, synonyms, translations

Individual evidence

  1. a b Andrea Gärtner, Leander Mölter, Andreas Gessner: Characterization of an impinger for the emission measurement of microorganisms . Hazardous substances - keeping the air clean , Volume 68 (2008) 6, pp. 351–356.
  2. VDI 4252 sheet 3: 2008-08 Recording of airborne microorganisms and viruses in the outside air; Active sampling of bioaerosols; Separation of airborne bacteria with impingers according to the principle of the critical nozzle (Measurement of airborne microorganisms and viruses in ambient air; Active sampling of bioaerosols; Separation of airborne bacteria with impingers using the principle of critical nozzle). Beuth Verlag, Berlin, p. 5.