GB1344701A - Apparatus for treating webs - Google Patents

Abstract

1344701 Web impregnation apparatus SIR JAMES FARMER NORTON & CO Ltd 31 Jan 1972 [10 Feb 1971 12 June 1971] 4350/71 and 27654/71 Heading D1L Apparatus for impregnating textile webs comprises a vacuum chamber 21 having a slot or other orifice past which a web 24 is moved, an impregnation bath 22 arranged immediately downstream of the vacuum chamber and an impervious vacuum-sealing belt 23 for moving the web 24 past and in close contact with the vacuum slot and past or through the impregnation bath. As illustrated (Figs: 1 and 3) the vacuum chamber 21 and impregnation bath may be situated in tandem in the same porous flexible metal cylinder 20, the chambers being disposed inside a tube 35 separated by partition 37 and having vacuum slot outlets 52 and impregnation liquid outlets 51 closely adjacent formed in a wearing plate 36 (e.g. of polyethylene) constituting the base of the two chambers. The porous metal cylinder 20 is preferably supported axially in annular mounting and bearing assemblies so as to rotate with the impervious belt 23 and web 24 passing thereunder, chambers 21 and 22 being fixed stationary inside the porous cylinder (Fig. 2, not shown). Liquid distribution and recovery apparatus and vacuum apparatus is also illustrated in Fig. 1, trough 29 being provided to collect excess impregnation liquid which is forced through the web 24. The vacuum opening may be formed by a series of staggered adjacent outlet holes and the impregnation outlet by an elongate slot or a row of orifices [Figs. 4, 6 and 13, not shown]. In operation the web 24 is fed between rotating porous cylinder 20 and impervious rotating endless belt 23 and passes under vacuum chamber 21 to be degassed, under the outlet to impregnation liquid chamber 22 where impregnating liquid is forced into the textile web and may then pass to suction box 32 which removes excess liquid or through the nip formed between squeeze rollers 31. Where the apparatus is to be used with volatile solvents the porous cylinder and belt arrangement may be located inside hinged covers connected to a solvent extractor (Fig. 9 not shown). In an alternative embodiment (Fig. 11) the impregnation chamber 22 located inside the porous cylinder may be replaced by a bath 85 formed by cylinder 80 and impervious belt 83 through which web 84 passes after being vacuum degassed as it passes vacuum slot 81. The porous metal cylinder 21 may be replaced by an endless rotating porous screen 82 (Fig. 10, not shown). Appropriate means (not shown) are provided for maintaining the liquid in trough 85.