Power sweeper filtering system

Claim 1

IN A MOBILE POWER SWEEPER, A CHAMBER HAVING A LOWER HOPPER SECTION FOR RECEIVING SWEPT ARTICLES, MEANS INCLUDING A BLOWER AND AN ARRAY OF AIR FILTER SHELL ASSEMBLIES COMMUNICATING WITH SAID CHAMBER SO THAT SUCTION AIR FLOWS BETWEEN THE HOPPER CHAMBER AND BLOWER AND IN SEPARATE STREAMS THROUGH THE FILTER SHEL''S IN SAID ASSEMBLIES, AND A MANIFOLD COMMUNICATING WITH THE INTERIORS OF SAID FILTER SHELLS AND THE BLOWER, EACH SHELL BEING COMPRISED OF AIR PERMEABLE MATERIAL FORMING MULTIPLE REENTRANT RECESSES, SAID SHELL ASSEMBLIES BEING CARRIED IN SAID ARRAY BY THE MANIFOLD AND BEING REMOVABLY ATTACHED THERETO SO AS TO PROJECT LENGTHWISE WITH ELEVATED EXPOSURE INTO OVERLYING RELATION TO THE LOWER INTERIOR OF THE CHAMBER IN SUCH MANNER THAT FILTERED PARTICLES GRAVITATE OUT OF SAID RECESSES INTO THE HOPPER SECTION, EACH ASSEMBLY INCLUDING AT LEAST TWO SHELLS HAVING FILTER PAPER SIDES EXTENDING GENERALLY VERTICALLY, ADJACENT SHELLS BEING CLOSELY SPACED IN SIDE BY SIDE RELATION AND SUPPORTED TO RESIST OUTWARD DISPLACEMENT OF THE SHELL MATERIAL FORMING SAID RECESSES AND TOWARD ADJACENT SHELL STRUCTURE FOR MAINTAINING GENERALLY VERTICALLY OPEN SPACING BETWEEN THE SHELLS ALLOWING FREE DOWNWARD DISCHARGE OF FILTERED PARTICLES FROM BETWEEN ADJACENT SHELLS.