Personal air purifying respirator

A respirator comprising:

• a head unit configured to be received on a human head;
• and
• a purifying unit configured to provide purified air to the head unit, the purifying unit comprising:
• a first housing portion having:
• an exterior side defining a partial filter chamber with a filter sealing surface, the exterior side including a tapered wall extending from the filter sealing surface to an inlet hole that is recessed from the filter sealing surface, wherein an outer filter wall extends from a periphery of the filter sealing surface, and filter-alignment tabs extending inwardly from the outer filter wall, and
• an interior side including an inner circular guide wall co-axial with the inlet, a circular blower-support wall circumscribing the inner guide wall, and an outer circular guide wall circumscribing the blower-support wall and defining a blower cavity, wherein the inner guide wall, the blower-support wall, and the outer guide wall are concentric with each other, the interior side further comprises a plurality of support posts located between the outer guide wall and the blower support wall,
• a second housing portion having an interior side including an inner circular wall and an outer circular wall that circumscribes the inner circular wall and that defines a blower cavity, wherein the first and second housings are attached to each other to form a housing such that the blower cavities are opposite each other to define a blower chamber within the housing,
• a blower disposed in the blower chamber and attached to the mounting posts, and
• a filter having an outer wall supporting a filter medium, the filter being received in the partial filter chamber with the outer wall disposed against the sealing surface and the alignment tabs and with the filter medium covering over the tapered wall and the inlet hole such that air entering the inlet hole passes through the filter.