Air intake stack and filter cartridge for fallout shelters

Claim 1

AN AIR INTAKE STACK FOR FALLOUT SHELTERS AND THE LIKE COMPRISING A LENGTH OF PIPE HAVING AN OPEN UPPER END, AN ELONGATED DEPENDING TUBULAR FILTER CARTRIDGE HAVING AN OPEN UPPER END AND A CLOSED LOWER END REMOVABLY FITTED WITHIN THE UPPER END OF THE PIPE AND HAVING AN OUTWARDLY EXTENDING ANNULAR FLANGE RESTING ON THE UPPER END OF THE PIPE WHEREBY THE CARTRIDGE ID DETACHABLY SUPPORTED WITHIN THE PIPE, A SEALING WASHER ENGAGING SAID FLANGE IN INTIMATE CONTACT WITH THE UPPER END OF THE PIPE, SAID CARTRIDGE INCLUIDNG INNER AND OUTER SHEETS OF SCREEN CLOTH AND A CENTRAL FILTERING MAT CONFINED THEREBETWEEN, SAID CARTRIDGE HAVING RADIALLY EXTENIDNG LONGITUDINALLY DISPOSED FLUTES, THE SHEETS WITH THE FILTER MAT BEING OVERLAPPED TO FORM A LONGITUDINAL SEAM, SAID FILTER MAT AT THE SEAM BEING EXTENDED BEYOND THE OUTER SHEETS AND FOLDED BACK ON ITSELF FOR IMTIMATE ENGAGEMENT WITH AN EDGE OF THE SEAM TO FORM AN AIRTIGHT STRUCTURE, SAID FILTER MAT AT THE LOWER END OF SAID BODY BEING EXTENDED BEYOND THE SHEETS, A TIE SECURING THE EXTENDED END OF THE MAT TOGETHER AND SAID EXTENDED TIE END BEING INSERTED WITHIN THE BODY, A PROTECTING HOOD FOR THE PIPE SURROUNDING THE UPPER END OF THE PIPE HAVING MEANS FOR DETACHABLY CONNECTING WITH THE PIPE, AND INWARDLY EXTENDING FEET CARRIED BY THE INNER SURFACE OF THE HOOD AND ENGAGING THE FLANGE FOR HOLDING THE FLANGE IN TIGHT CONTACT WITH THE UPPER END OF THE PIPE.