Apparatus for forming nonwoven webs

Claim 1

IN AN APPARATUS FOR THE PREPARATION OF NONWOVEN WEBS WHEREIN A MOVING FLUID MEDIUM TRANSPORTING A PLURALITY OF FILAMENTS IS DIRECTED TOWARD THE LAYDOWN ZONE ABOVE A MOVING FORAMINOUS RECEIVER AND THE FILAMENTS ARE RETAINED BY THE RECEIVER WHILE THE FLUID MEDIUM PASSES THROUGH, THE IMPROVEMENT COMPRISING A PLENUM CHAMBER POSITIONED BENEATH THE RECEIVER DIRECTLY BELOW THE LAYDOWN ZONE, SAID PLENUM CHAMBER COMPRISING A BOTTOM, END WALLS, SIDE WALLS, A PERFORATED COVER PLATE, AN ORIFICE PLATE INTERMEDIATE THE COVER PLATE AND THE BOTTOM AND IN GAS-TIGHT ARRANGEMENT WITH THE END WALLS AND SIDE WALLS, THE OPENINGS IN THE COVER AND ORIFICE PLATES BEING UNIFORMLY DISTRIBUTED AND A MULTIPLICITY OF INDEPENDENT FLUID-DIFFUSION CELLS LOCATED BETWEEN THE COVER PLATE AND THE ORFICE PLATE, THE CELLS BEING OPEN AT BOTH ENDS, THE LOWER END OF EACH CELL BEING IN CONTACT WITH THE ORIFICE PLATE AND POSITIONED OVER A SINGLE HOLE IN THE ORIFICE PLATE AND THE UPPER END OF EACH CELL BEING IN CONTACT WITH THE COVER PLATE AND COMMUNICATING WITH OPEN AREA OF SAID PLATE, THE ORIFICE PLATE OFFERING SUBSTANTIAL RESISTANCE TO THE FLOW OF THE FLUID MEDIUM, AND SAID PLENUM CHAMBER HAVING AN OUTLET BELOW THE ORIFICE PLATE FOR REMOVAL OF THE FLUID MEDIUM FROM THE CHAMBER.