GB1341932A - Method of forming a fibrous web from a strand of textile length fibres - Google Patents

Abstract

1341932 Mechanical treatment of fibres KENDALL CO 30 June 1972 [2 July 1971] 30806/72 Heading DIF In a method of forming a fibrous web a twist-free strand, e.g. of viscous rayon and 30,000-500,000 denier, of staple fibres is fed through an open ended guide tube, with the strand filling the inlet end of the tube and travelling without alternation through the major part of the length thereof, into a stream of gaseous fluid, e.g. air or steam, concentric with the strand and flowing over the exit end of the tube in the same direction as the strand at a velocity sufficient to draft the strand into an alernated fluid-borne stream of separated fibres entrained by the fluid, and the fibres from the stream are deposited to form the web. The stream may be decelerated by diffusion into a plenum chamber and drawn therefrom in the form of a fibrous web. In the operation of an aspirator 10 having a nozzle 23, Fig. 1, air fed under pressure through inlet 14, is converted to a convergent stream in a section 21 whence it diverges in the section 25 as a stream concentric with guide tube 22 and travelling at supersonic velocity. Air flowing from outlet 26 creates a low pressure zone in a guide tube 16 into one end of which a strand 19 is stuffed by rolls 17. As the strand approaches the exit end of tube 16, fibres are plucked therefrom in an alternating (ratio of more than 5000) stream and travel therebeyond at approximately the velocity of the stream in the divergent end of the nozzle. The fluidborne stream of fibres passes successively through compartments 30, 32, 34 of a plenum chamber, Fig. 3, the partitions 36, 38, of which act as baffles, and a uniform flow at reduced velocity of fibres emerges from the outlet 48 to impinge on the surface of a porous conveyor belt 50 (opposite a vacuum box 52) and form a web 54. If the web is to be laminated with another substrate, a layer of permeable supporting material such as gauze, cellulose tissue or porous non-woven fabric may be interposed between the conveyor belt and the fibrous stream.