Patent ID: 7326269
Filing Date: 2008-02-05
Classification: B01D,F24F,Y10S

Abstract:
1. A nuclear, biological, and chemical (NBC) filtration unit for use with a portable environmental control unit (ECU) comprising: a first air flow path allowing air flow from an external environment, through a filtration unit, and to said ECU without said air passing through an NBC filter; a second air flow path allowing air flow from said environment, through an NBC filter in said filtration unit and to said ECU; a controller allowing said filtration unit to switch from passing air through said first air flow path to said second airflow path and from said second air flow path to said first air flow path repeatedly without said NBC filter being removed from said filtration unit; and a plurality of valves arranged in said first and second air flow path and controlled by said controller; wherein, prior to said controller switching from said second air flow path to said first air flow path, said plurality of valves are arranged so that air passes along said second air flow path from said environment through said filtration unit and said NBC filter and then through said first air flow path back to said environment to purge said first air flow path of any contaminants in said first air flow path.