Portable air filtration device

Claim 1

A portable air filtration device comprising, in combination: a rigid five-sided peripheral container defining an internal chamber and having larger horizontally orientated upper input orifice and a smaller vertically orientated output orifice; a filter member, carried in the input orifice, having a first filter screen of a lenticular shape with an outwardly extending planar rim for support in the input orifice of the peripheral container and a second cooperating substantially planar filter screen having a peripheral rim adjacent the rim of the first filter screen to define a lenticular chamber between said first and second screens, said chamber being of size sufficient to contain at least ten pounds of particulated charcoal, each said filter screen defining an area of at least approximately 384 square inches with defined orifices comprising at least seventy-five percent of said area and no orifice having a major dimension greater than about 0.06 inch, and releasable means for mechanically fastening the first filter screen with its rim in adjacency to the rim of the second filter screen in the aforesaid input orifice; particulate activated charcoal, having a particle size larger than the orifices defined in the screen elements, carried in the chamber defined between said first and second filter screens in a lenticularly shaped mass to cause substantially uniform air flow through all portions of said charcoal mass; and a fan member carried within the internal chamber defined by the peripheral container to receive air from the internal chamber and force that air at a rate of at least about 465 cubic feet per minute through the output orifice defined in said container to create a flow of air from about the peripheral container through the filter member in the input orifice and out of the output orifice defined in the peripheral container.