GB499038A - Improvements in or relating to respirators for use in atmospheres containing carbon monoxide - Google Patents

Abstract

In a respirator for use in atmospheres containing carbon monoxide wherein the latter is removed from the inspired air by catalytic oxidation after passage through a drying medium, the drying medium comprises two layers of material disposed in succession in the path of the air, and composed, the first of fused zinc chloride dispersed on a carrier, preferably active charcoal, and the second of a granulated mixture of calcium chloride and fused zinc chloride. A third layer composed of magnesium perchlorate granules may be provided. The material of the first layer may be made, for example, by mixing 9 parts of dry charcoal granules with 15 parts of fused zinc chloride, and stirring the mixture until cool enough for the granules to remain non-adherent to one another, and that of the second layer by mixing powdered anhydrous calcium chloride with about 20 per cent of fused zinc chloride, and when cold, granulating the mixture. Reference is made to the use of the known oxidizing catalyst for carbon monoxide consisting of a mixture of manganese and copper oxides to which a small quantity of another oxide, such as of silver is added.