Method for producing filters

Claim 1

IN A PROCESS FOR PRODUCING FIBROUS FILTER BODIES, THE STEPS COMPRISING PASSING A COLLECTING SURFACE THROUGH A CHAMBER, DIRECTING TWO SPACED SEPARATE GAS STREAMS TOWARD THE COLLECTING SURFACE, THE CONES OF DELIVERANCE OF THE GAS STREAMS ONLY PARTIALLY OVERLAPPING EACH OTHER AT THE COLLECTING SURFACE, INTRODUCING INTO ONE GAS STREAM COARSE FIBERS AND INTO THE OTHER GAS STREAM FINE FIBERS, THE GAS STREAMS BEING SPACED TRANSVERSELY WITH RESPECT TO THE DIRECTION OF TRAVEL OF THE COLLECTING SURFACE, DEPOSITING THE FIBERS FROM THE GAS STREAMS IN RANDOM DISTRIBUTION ON THE COLLECTING SURFACE IN THE FORM OF A WEB, THE RELATIVE PROPORTIONS OF THE COARSE FIBERS ALONG ONE EDGE OF THE WEB OF COLLECTED WEB VARYING TRANSVERSELY ALONG THE WEB FROM SUBSTANTIALLY ALL COARSE FIBERS ALONG ONE EDGE OF THE WEB TO SUBSTANTIALLY ALL FINE FIBERS ALONG THE OPPOSITE EDGE OF THE WEB, CUTTING THE WEB INTO TRANSVERSE STRIPS AND ROLLING THE STRIPS UPON THEMSELVES FROM A TRANSVERSE EDGE TO FORM A COIL OF FIBROUS MATERIAL, THE AVERAGE FIBER DIAMETER IN THE COIL VARYING RADIALLY FROM THE DIAMETER OF THE FINE FIBERS TO THE DIAMETER OF THE COARSE FIBERS, THE COIL OF FIBROUS MATERIAL HAVING THE PROPERTY OF FILTRATION IN DEPTH.