| abstract |
Apparatus for treating a supply of compressed air containing carbon monoxide but substantially devoid of free water and of relative humidity sufficient for comfortable breathing, to render it suitable for breathing purposes. The apparatus comprises four sequential filters for preliminary removal of bulk liquids, particulates, carbon dioxide, oil and water aerosols, and hydrocarbon vapors and odors and a pressure vessel (21) having a heater (39) at its inlet to which the air is supplied without any drying treatment. The heater comprises at least one heating element formed of a material which exhibits a rapid increase in electrical resistance at a temperature of from 101° C. to 110° C. From the heater the air passes to and through a bed of granular catalyst material within the pressure vessel, the catalyst oxidising CO in the air to CO 2 . A temperature sensor (37) within or immediately downstream of the catalyst bed controls the heater to maintain a mean bed temperature of not less than 100° C. during air passage therethrough, so effecting a temperature change in the water vapour in the air to avoid poisoning of the catalyst. The air passing from the bed is delivered cooled, but not further treated, for breathing purposes. |