Air-laying process for forming a web of textile fibers

Claim 1

In a process for forming a web of textile fibers wherein staple fibers are dispersed in a flow of air and then collected on a moving screen to form a random fiber web; the improvement which comprises projecting staple fibers at a uniform initial velocity of at least 3,000 feet per minute into a controlled flow of air at an angle of less than 25* with the direction of said flow to form a thin stream of fibers; controlling the flow of air so that the fibers are projected into a region of stable air flow characterized by (a) an average air velocity (V) between 0.5 and 3.5 times said initial fiber velocity, (b) an average velocity variation in each 0.1-inch thick layer across the thickness of said region, excluding the first 0.1-inch layer next to any wall, which is less than + OR - 15 percent of said velocity (V), (c) a velocity variation across the width of said region which is less than + OR - 10 percent in any one foot increment, and (d) an average turbulence intensity of no more than 15 percent; controlling the flow of air to transport the fibers to the collecting screen as a thin fiber stream in a stable flow of air characterized by (e) an average air velocity between 0.25 and 3 times said velocity (V) and (f) an average turbulence intensity in the fiber path of no more than 15 percent; and then separating the fibers from the flow of air to form a uniform web on the moving screen.