Abstract: A filter for a gas mask has a concave outlet wall and a convex inlet wall with a particulate filter bed that has a uniform depth and conforms substantially to the shape of the inlet and outlet wall. The side wall can have an elliptical, circular or convex shape to conform to the curvature of the wearer's face, or a planar shape. The filter an be a double particulate filter element and a double adsorption filter element configured for axial airflow therethrough with a bifurcated flow pattern. The adsorption filter element comprises a granulated charcoal, a composite material having carbon particles combined with binder particles, or an immobilized bed of charcoal granules and EVA-coated fibers.

Abstract: A filter for a gas mask has a concave outlet wall and a convex inlet wall with a particulate filter bed that has a uniform depth and conforms substantially to the shape of the inlet and outlet wall. The side wall can have an elliptical, circular or convex shape to conform to the curvature of the wearer's face, or a planar shape. The filter an be a double particulate filter element and a double adsorption filter element configured for axial airflow therethrough with a bifurcated flow pattern. The adsorption filter element comprises a granulated charcoal, a composite material having carbon particles combined with binder particles, or an immobilized bed of charcoal granules and EVA-coated fibers.

Abstract: A filter for a gas mask has an elliptical or circular, convex shape to conform to the curvature of the wearer's face, or a planar shape. The filter comprises a double particulate filter element and a double adsorption filter element configured for axial airflow therethrough with a bifurcated flow pattern. The adsorption filter element comprises a granulated charcoal, a composite material having carbon particles combined with binder particles, or an immobilized bed of charcoal granules and EVA-coated fibers.

Abstract: An integrated system, process and apparatus are provided for the efficient and effective recovery of spent pulping liquors, particularly kraft black liquor, whereby in an initial stage concentrated spent liquor is subjected to combustion in a reactor equipped with a plurality of particulate materials, at least one of which is of finer particle size than the other, preferably subjecting a portion of said particulate materials to at least one further treatment in a fluidized bed unit, and treating the inorganic solid combustion products in a reducing atmosphere.