GB885379A - Improvements in and relating to the production of unwoven fabrics - Google Patents

Abstract

885,379. Agglutinated fibrous materials. WEST POINT MANUFACTURING CO. Jan. 28, 1958 [Feb. 1, 1957], No. 2779/58. Class 140. [Also in Group IX] Apparatus for the production of unwoven fabric comprises means to provide a moving source of fibre supply by attenuation of a fibre lap, a fibre transfer duct having an open fibre-receiving end extending across the width of the moving source of fibre supply and in communication therewith, with the edges defining the width of the duct end being spaced from the source of fibre supply to form air inlets, an endless foraminous fibre-receiving member at the opposite discharge end of the duct and means for creating an air stream through the air inlets, duct and foraminous member to remove fibres from the attenuating means and transfer them through the duct to the foraminous member to form a web thereon, in which the fibre transfer duct has a first section extending from the fibre-receiving end and merging into a second section terminating at the discharge end, the first section having a substantially constant cross-sectional area throughout its longitudinal extent and the second section being of substantially constant width throughout its longitudinal extent and increasing - in crosssectional area longitudinally towards the discharge end. As shown in Figs. 1 and 3, the apparatus includes a card cylinder 10 and a driven endless foraminous member or screen 12 trained about rollers 34, 36, 38, 40, 42 to which the fibres from the card cylinder are transferred by means of an air stream through fibre transfer duct 14. Sealing means co-operate with the ends of the transfer duct adjacent the foraminous screen 12 whereby undesired air currents are prevented. The duct system includes receiver duct section 16 mounted on the opposite side of screen 12 and terminating in throat 18. Cylindrical take-off duct 20 is connected throughout its width with throat 18 and communicates also with a second cylindrical duct 22 leading to a means for creating an air stream such as a fan (not shown). Fibre laps are fed to the card cylinder and are attenuated during their movement in the latter and when they reach a point adjacent the inlet of the transfer duct 14 the stream of air entering the duct strips the fibres from the card cylinder and carries them through duct 14 to the screen 12. The web so formed is doffed therefrom adjacent roller 38 and passes over roller 246, Fig. 8, and thence constitutes the output of the apparatus as indicated at 278. The transfer duct 14, as shown in Figs. 1 and 3, includes a first section 100 which diverges in width and converges in height outwardly from the card cylinder, the cross-sectional area preferably remaining constant, and a second section 102 of substantially constant width and which diverges in height as it approaches the foraminous member. Section 100 is arranged to spread the fibres received at the forward end so that a web of greater width than the card cylinder is produced. By expanding the height of the second section 102 the fibres are presented to the foraminous member in such a manner that the tendency of the fibres to lie parallel to each other across the width of the foraminous member is reduced to a minimum. The present invention is stated to constitute an improvement in the procedure and apparatus disclosed in Canadian Specification 496,390 wherein impregnation of the web with binder is described.