Patent ID: 7387652

Claim:
A filter assembly for providing filtered air to an enclosed space for a human occupant, said filter assembly comprising: a housing having: an exhaust port for connecting to the enclosed space, an internal air intake port for connecting to the enclosed space, and an external air intake port for connecting outside of the enclosed space; means for providing a partial vacuum to said air intake ports, said means including a motor; a pre-filter; and a purification filter within said housing, wherein said filter assembly is arranged such that said filter assembly is adapted for simultaneously filtering recirculated air drawn from said enclosed space via said internal air intake port and filtering external air from the outside of the enclosed space via said external air intake port, wherein said filtered air is provided to the enclosed space via said exhaust port, wherein the motor pulls a stream of air through said air intake ports, the prefilter and the purification filter and pushes the stream of air through the exhaust port, said stream of air providing a positive pressure to the enclosed space relative to the outside of the enclosed space, and wherein the motor is located downstream of the purification filter, and the purification filter is located downstream of the pre-filter.