NBC filtration system with air exchange backup unit

Abstract

A near ceiling mounted NBC filtration system of collective protection shelters comprising a filter unit, a blower, and an air exchange backup unit [20] (FIG. 5). The air exchange backup unit [20] comprising: a plurality of hinged segments [22a, b, c] serially linked to each other to form a foldable arm. The hinged segments [22a, b, c] are configured for transmission of rotational motion between each other. At least one of the hinged segments comprises at least one stage of a first speed increasing transmission. A first end [24] of the air exchange backup unit is swiveably attached to an electric motor [42] driving a blower [40]. And a second end [26] of the air exchange backup unit carries a detachable hand crank [28]. Manual rotation of the hand crank [28] rotates a shaft of the electric motor [42] at substantially a rated speed of the electric motor. The second end [26] of the air exchange backup unit is firmly attachable to a wall of the protection shelter at a convenient position for manual cranking of the hand crank [28]. The air exchange backup unit [20] is selectively folded up at normal times.

Dependencies are inferred from the claim text.