Method of forming a fibrous web using a variable transverse webber

DETAILED DESCRIPTION The present invention is directed to the high-speed production of blends of long and short fibers that result in a wide variety of composite nonwoven web structures of different widths, thicknesses, shapes and compositions.
In an illustrative embodiment of the invention two independent fiber sources driven by feed rolls are individualized by parallel counter-rotating lickerins.
The individualized fibers are doffed from the lickerins by air streams and centrifugal force, and are carried to a mixing zone.
The fibers may be randomly and uniformly mixed in the zone or may be segregated by type, and then directed to a condensing zone where they are deposited onto a narrow condensing screen which is located in the condensing zone.
The mixing zone is below the parallel lickerins and is defined generally by the space between the lickerins and the condensing zone, which is below the mixing zone.
The screen is moved parallel to the axes of the lickerins, which is transverse to the conventional orientation.
The motion of the screen with respect to the lickerins and the frame which houses them defines an input or rear end of the condensing zone, where the screen first enters the condensing zone and receives individualized fibers, and an exit or front end, where the formed web ceases to receive fibers and is expelled from communication with the condensing zone.
At any given moment during operation of the apparatus, the web is formed in the condensing zone between the input and exit ends, which also generally define the operating length of the lickerins.
Duct plates are used to additionally define a path between the lickerins and the condenser screen, and a vacuum chamber with a slot located below the screen is preferably used to form the air streams that doff the fibers from the lickerins and help deposit the fibers onto the screen.
Since the screen travels parallel to and between the lickerins axes, there is a high-speed transverse formation of a web of nonwoven fibers.
The transverse webber according to the invention provides a long web formation zone whose length is limited only by the practical length of the lickerins and whose width is limited only by the practical duct configuration between the lickerins and the screen