Standard Telephones and Cables Public Limited Company

Malcolm D Mackay

Andrew P Harrison

A variable-temperature pressure coating system for optical fibres, particularly for uv-curable primary coatings, includes a gas cylinder (8) for pressurizing a tank (1) of coating material, and a heat exchanger (15) controlling the temperature and thus the viscosity of the coating material supplied to a die chamber (19) through which an optical fibre (18) is passed following drawing. The temperature of the die chamber may also be controlled by the same circuit as the heat exchanger. A valve (14) serves to control flow to the die and to enable priming of the tube (13) by filling with coating material (and removal of air bubbles) prior to supply thereof to the die chamber (19). The system is designed for ease of operator handling together with production of high quality coatings at high speed.

Optical fibre manufacture

A rod-in-tube method of manufacturing optical fibre where the rod and the tube are fed into the heating zone of a furnace at different rates, the rod feed rate being greater than the tube feed rate. The rod is mounted relative to the tube such as to permit self-centering of the rod in the tube when the tube collapses onto the rod in the heating zone. The drawn fibre may be monitored by means of an in-line fibre core to O/D monitor and feed-back employed to drive the tube and rod feed mechanisms accordingly thereby providing precise control of the core to O/D ratio of the fibre. Very long fibre lengths may be achieved by feeding the rod into the heating zone at a greater rate than a very large mass tube billet and consecutively feeding further rods into the tube billet as the preceding rod is used up.

Growing community of inventors

Harlow, United Kingdom

Malcolm D Mackay