METHOD OF PREPARING NITROGEN-HYDROGEN PROTECTIVE ATMOSPHERE Russian patent published in 2003 - IPC

FIELD: industrial protective means. SUBSTANCE: nitrogen-hydrogen atmosphere used as protective atmosphere in industry is prepared by high-temperature combustion of hydrocarbon gases in layers of granulated refractory material, volume of which increases from precedent layer to subsequent layer at variable volumetric flow rate between 2500 h^-1 and 250 h^-1. Combustion begins at higher flow rates and ceases at lower ones, whereas ratio of volumetric flow rate to specific surface of each refractory material layer is equal to 5-9, and volume of each next layer increases by 5-10%. As a result, residual oxygen level in protective atmosphere drops to 0.0001 vol %. EFFECT: reduced residual oxygen in protective atmosphere. 3 cl, 1 tbl