US Patent 9744493 Air filtration device

Air filtering devices are disclosed that contain a first filter cartridge having a cartridge inlet and a cartridge outlet and a curved filter bed having a concave surface disposed such that air to be filtered passes through the inlet, the curved filter bed, and the outlet. The air filtering devices also contain a blower assembly having a blower inlet in fluid communication with the cartridge outlet and a blower outlet, the blower assembly includes a motor proximate to the concave surface of the curved filter bed. The motor has a rotational axis such that the rotational axis is adjacent to the center of curvature of the curved filter bed. The air filtering device may be used in powered air purifying respirators.