GB674223A - Process and apparatus for the machine production of rod or tubular multiple-layer bodies, made of glass - Google Patents

Abstract

674,223. Glass rods and tubing. SCHULLER, W. April 20, 1949 [April 20, 1948], No. 10933/48. Class 56. Glass tubing e and glass rods of multiple layers of glass or with coloured glass stripes are formed by the continuous up-drawing of a rotating glass batch a to which an additional glass batch d, of other composition or different colour or colours, is fed at the same rotating speed through a double walled cylinder 5 having its lower edge dipping into the glass batch a. The cylinder 5 is rotated with the pot 4 by means of teeth 7 and consists of external and internal parts 8 and 9 which surround an annular cavity 10 and are connected at 11. The glass d, with the same or nearly the same coefficient of expansion as glass a, is fed into the cavity 10 and is sucked into the forming position b, forming a coat 14 completely covering the tubing e. The lower edge of the part 8 may be immersed more or less than that of the part 9. The apparatus may be provided with a water &c. cooling device 15, as shown, or with a device operated with a gas coolant. The lower edge of cylinder 5 may be provided with a floating protective ring 25 which is not secured thereto, and the ring may be spaced from the cylinder so that heat passes from the space round the cylinder in the direction of arrow B, as shown in Fig. 7, and prevents the batch d from chilling. The tube or rod is given a coating in the form of one or more stripes by using a cylinder 18 which has, instead of the annular cavity 10, a cavity 19 extending over a part of the circumference only, or a number of spaced cavities such as 21. With such cylinders the glass d is conveniently fed from a spoon or funnel to each cavity. The apparatus shown in Fig. 7 has a nozzle 27 with bore-hole 28 through which air is blown to form the tubing. The apparatus for forming rods is similar but does.not include the nozzle and borehole.