GB1475997A - Manufacture of coated glass fibres - Google Patents

Abstract

1475997 Coating glass fibre TELEPHONE CABLES Ltd 3 Dec 1974 [3 Sept 1973] 41336/ 73 Heading B2E A coated glass fibre, which may be solid or tubular, is made by progressively feeding a solid body of vitreous material into a heating zone maintained at a sufficiently high temperature to cause progressive melting of the leading end of the body, drawing a glass fibre downwardly from the molten end surface of the body and out of the heating zone to solidify on cooling, coating the fibre with a plastics material in liquid form, and causing the liquid to set to form a protective coating, the steps being carried out continuously and successively and the coating step being effected before the fibre engages any drawing, guiding or other apparatus. In particular, the fibre may be passed through a housing 13 containing a body of felt 14 which is impregnated and partially filled with liquid thermosetting plastics material 16. The lower portion of the felt body may remove excess coating material as the fibre passes through the exit orifice of the housing or an upward gas pressure may be provided in this orifice to prevent leakage. Alternatively, the fibre may be passed around a pulley 31 having a grooved or channelled rim into which the plastics material is fed from a reservoir 33, this rim thereby providing a fluid bearing for the fibre lubricated by the liquid plastics, and thence to a curing oven 17. In either method of coating, the plastics may be polyurethane solution, polyvinylacetal or polyester and the fibre is drawn through or around the coating means by means of a drum driven in synchronisation with the lead screw of the feeding machanism for the vitreous material to give a coating of constant thickness.