Production of thick, laminated, fibrous structures

Claim 1

THE METHOD OF PRODUCING A FIBROUS STRUCTURE HAVING LAYERS OF TINE FIBERS IN THE OUTER WALL PORTIONS AND LAYERS OF LOW COST, COARSE FIBERS THEREBETWEEN COMPRISING THE STEPS OF FORMING A PLURALITY OF AIR STREAMS, PASSING EACH AIR STREAM FIRST THROUGH A STATIONARY SEPARATING WALL HAVING FORAMENS DIMENSIONED TO PERMIT PASSAGE TO FIBERS AND THEN THROUGH A COLLECTING WALL SPACED A SHORT DISTANCE FROM THE SEPARATING WALL AND HAVING FORAMENS DIMENSIONED TO SEPARATE FIBERS FROM THE AIR STREAM AS IT PASSES THERETHROUGH, ENTRAINING FIBERS OF FINE DENIER AND HIGH INTRINSIC STRENGTH THROUGH THE FIRST AND LAST, AIR STREAMS AND COARSE FIBERS OF LOW COST IN INTERMEDIATE AIR STREAM THEREBETWEEN, PASSING THE SEPARATING WALL IN CONTINUOUS FASHION ACROSS THE AIR STREAM WHEREBY A LAYER OF FINE FIBERS ARE FORMED ON TOP AND BOTTOM WITH LAYERS OF COARSE FIBERS THEREBETWEEN, WITHDRAWING LARGER VOLUMES OF AIR THROUGH THE COLLECTING WALL THAN IS PASSED WITH THE FIBERS THROUGH THE RESPECTIVE SEPARATING WALL WHEREBY A SLIGHT INFLOW OF AIR FROM THE SURROUNDING ATMOSPHERE TAKES PLACE BETWEEN THE SEPARATING WALL AND THE COLLECTING WALL TO PERMIT THE COLLECTING WALL TO PASS THROUGH THE AIR STREAM WHOLE REMAINING OPEN TO THE ATMOSPHERE AND SPRAYING BINDER PARTICLES INTO SELECTED AIR STREAMS IN ADVANCE TO PASSAGE THROUGH THE COLLECTING WALL OF DEPOSITION OF SUCH BINDER PARTICLES WITH THE FIBERS ON THE COLLECTING WALL.