FILTERING CARTRIDGE Russian patent published in 2003 - IPC

FIELD: individual equipment for protecting respiratory organs. SUBSTANCE: filtering cartridge has casing with branch pipe, netted cover with ring, burden placed in casing, upper and lower burden securing grids, and folded filter located between cover and upper grid. Peripheral fold of folded filter is fixed on cover ring between ring and casing. Casing section contour has one plane of symmetry and is defined by two arcs of circles of unequal radii, which are connected through low curvature arcs or parts of tangent lines. Filter fold pitch is reducing from peripheral part to center. Fold apex arc radii are determined from following expressions: where is apex arc radius of fold faced toward burden, m; is apex arc radius of fold faced toward cover, m; R₀ is inner radius of cover ring, m; Δ_i is fold pitch, m; q_i is increment of radii; n is number of folds. Centers of arcs of circles defining filter fold apexes are positioned on axis of symmetry arranged in plane of symmetry of casing. Filtering cartridge is designed for protecting individual's respiratory organs from hazardous environment, such as reactive gases, vapors, aerosols. EFFECT: increased efficiency and enhanced reliability in operation. 2 dwg, 1 ex