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Title
Verfahren und Vorrichtung zum Herstellen und Abfuellen von quantitativ definierbaren Gasgemischen mit Komponenten in sehr geringer Konzentration
Date Issued
2000
Author(s)
Sohn, H.
Steinhanses, J.
Patent No
1998-19858366
Abstract
Die Erfindung betrifft ein Verfahren zum Herstellen und Abfuellen eines quantitativ definierbaren Gasgemisches aus einem Traegergas mit mindestens einer weiteren Komponenten in sehr geringer Konzentration, umfassend die Schritte: (a) dynamisches Erzeugen eines Gasstroms aus dem Traegergas und der oder den interessierenden Komponente(n) in konstantem Mischungsverhaeltnis mit Hilfe eines Kapillardiffusions-Dosiersystems, (b) Durchleiten des so erzeugten Primaergasstroms durch eine Falle und Einfangen der interessierenden Komponente(n) aus dem Gasstrom in dieser Falle ueber einen definierten Zeitraum hinweg, (c) Durchleiten eines Spuelgasstroms durch die Falle, quantitatives Ueberfuehren der interessierenden Komponente(n) in diesen Spuelgasstrom und Einleiten des erhaltenen Gasgemischs in einen zuvor evakuierten Gasbehaelter.
DE 19858366 A UPAB: 20000818 NOVELTY - Gas mixtures of standardized composition are prepared with a capillary diffusion system, mixing constant proportions of the substance of interest with the carrier gas stream, passing the primary gas mixture through a low temperature trap to separate the substance of interest, purging a controlled amount of the same or a different gas through the trap to re-suspend the substance of interest and provide the required concentration and charging the product gas mixture to an evacuated container. DETAILED DESCRIPTION - Gas mixtures of standardized composition are prepared from a carrier gas in admixture with very low concentrations of volatile substances, by using a capillary diffusion system to mix constant proportions of the substance of interest with the carrier gas stream. The primary gas mixture is passed through a low temperature trap to separate the substance of interest. A controlled amount of the same or a different gas is purged through the trap to re-suspend the substance of interest and to provide the required concentration and the product gas mixture is charged to an evacuated container. Preferred Features: Mixing of a constant proportion of the substance of interest with the carrier gas stream is performed at an upstream pressure of approximately 50-200 kPa. The product gas mixture is at a pressure of 1000-10000 kPa. Typical capillary dimensions for preparing a mixture of trace aromatics in nitrogen or air are 5 cm length by 0.1 cm diameter for benzene, 0.2 cm for toluene, and 0.4 cm for xylene and ethylbenzene. USE - Preparation and storage of standard gas mixtures for instrument calibration and equipment testing, etc. ADVANTAGE - The technique allows the preparation of very low concentration mixtures, i.e. of the order of microlitre/m3.
Language
de
Patenprio
DE 1998-19858366 A: 19981217