GB396864A - Absorption filter for respirators - Google Patents

Abstract

Gas filters for use in respirators comprise sponge rubber the pores of which are lined with a gas-absorbing substance, preferably by kneading into the sponge an aqueous chemical paste which may also contain moistening agents, powdered adsorbents such as active carbon or silica gel, or binding, stiffening or setting agents such as cement, dextrin, starch, asbestos powder or water glass. The sponge rubber may subsequently be rigidified by vulcanization, for example with sulphur chloride vapour. Examples of suitable plastics are: (1) for absorbing acid gases, potassium metasilicate or a mixture of this salt with potassium carbonate, 12 parts, active carbon, 4 parts, powdered cement, 5 parts; hexamethylene tetramine or complex zinc salts such as zincates or zincammines may be added; (2) for absorbing ammonia, cuprous chloride and active carbon, in equal parts.ALSO:A filter element for use in respirators comprises sponge rubber the pores of which are lined with a gas absorbing substance, preferably by kneading into the sponge an aqueous chemical paste which may also contain moistening agents, powdered adsorbent such as active carbon or silica gel, or binding, stiffening or setting agents such as cement, dextrin, starch, asbestos powder or water glass. The sponge rubber may subsequently be rigidified by vulcanization, for example with sulphur chloride vapour. Examples of suitable pastes are:-(1) for absorbing acid gases, potassium, metasilicate or a mixture of this salt with potassium carbonate, 12 parts, active carbon, 4 parts, powdered cement, 5 parts; hexamethylenetetramine or complex zinc salts such as zincates or zincammines may be added: (2) for absorbing ammonia, cuprous chloride and active carbon, in equal parts.