Insulating Gas Mask with Hybrid Air Duct Design and Unevenly Loaded Regenerative Cartridge

According to stoichiometric estimates, less than half of the protective resource of an insulating mask with chemical oxygen redundancy is used by the moment of critical breakthrough of exhaled СО2 through the regenerative cartridge. One of the causes is the destruction of the porous structure of oxygen-containing product granules affected by exothermic heat emitted during the chemisorption of exhaled СО2 molecules. The second cause is the dead layer of the product remaining unused by the end of the protective action of the gas mask when air with 1.5 % carbon dioxide content starts leaving the regenerative cartridge. In order to eliminate these causes, mathematical and computer modeling of air regeneration in the gas mask for chemically bound oxygen with a hybrid (circular pendulum) air duct design and enlarged granules of potassium superoxide at the inlet to the regenerative cartridge have been performed. It has been shown that the enlargement of granule size by 25 % reduces by more than one-third the rate of heat emission in them when binding exhaled СО2 molecules, which softens the cartridge's thermal regime and preserves the granules' porosity. The length of the part of the cartridge with enlarged granules is determined based on the condition of the equal rate of СО2 absorption at the inlet to the first and second (with non-enlarged granule size) parts of the cartridge. The efficiency of the use of the breathing device’s protective resource is also increased by the reverse of airflow in the dead layer of oxygen-containing product. The length of the pendulum part of the regenerative cartridge that ensures the maximum (by 8.1 %) increase in the use of the product’s dead layer and prevents air filtration through the spent layers of oxygen-containing product has been determined.