GB1395354A - Method of mixing at least two gases and to a device for carrying out said method - Google Patents

Abstract

1395354 Mixing gases ENTREPRISE DE RECHERCHES ET D'ACTIVITES PETROLIERS (ELF) 21 June 1972 [29 June 1971 1 Dec 1971] 29043/72 Heading B1C In a method and apparatus for mixing a molar proportion of a gas B with a gas A, the latter flows through a mixing chamber 3 at a constant rate while B diffuses into it from a chamber 2 through a porous screen 4. The gas B may, as shown, be the vapour of a volatile liquid maintained at a constant level in chamber 2, or may be introduced in the chamber 2 in the gaseous state; in the latter case a pressure equalisation duct (14, Fig 3 not shown) may connect the two gas supply pipes. The apparatus is surrounded by a temperature controlled enclosure. The area of the screen through which gas B can diffuse may be altered by exchanging the ring 5. The screen may be a sintered metal plate, glass fibre pad, wire guage, or a thin permeable membrane e.g. of a silicone, polyalkylene, polyethylene or polypropylene, of thickness 0.5Á to 1 mm and pore diameter 1Š to 1 mm. More than two gases can be mixed by introducing a mixture of gases or liquids with the the chamber 2, or by using a plurality of such chambers, the different gases diffusing through the same screen. The invention is useful in chromatography, preparing standard mixtures for analytical purposes, and making doping gas mixtures.