Patent GB-349315-A (GB)
Title: Process for the manufacture of glass tubes and automatic apparatus embodying the same
IPC: C03B17/04
Filed: 1930-05-30
Abstract: 349,315. Making glass tubing. VELLO, L. SANCHEZ-, 2, Avenue Charles V, Nogent-sur-Marne, Seine, France. May 30, 1930, No. 16776. Convention date, June 8, 1929. [Class 56.] A method of making glass tubing consists in flowing molten glass through an aperture in the floor of a container around a stem having a conical end. The glass flows vertically downwards in the form of a tube and is drawn away horizontally by mechanism which also causes it to rotate. A device is also provided for stirring the glass in the forehearth to keep its viscosity constant. The container for the molten glass consists of a forehearth 1, Fig. 3, attached to a tank furnace, and the aperture B through which the glass flows is surrounded on its underside by a wall 24 enclosing a ring of burners around the aperture. A vertical tubular stem 9 projects into the aperture, and has a conical lower end 11 which constitutes a former for the glass tube. A passage 11a, inclined to the axis of the stem 9, connects the bore of the stem with the space within the former 11. The stem is supported by a table which can be moved in two directions horizontally by screws in order to adjust the position of the stem in the aperture B. The stem can also be moved vertically by a worm wheel 14, and can be rotated by means of a gear wheel 18 connected to an electric motor. A sleeve 20 surrounds the stem and is rotated bv an electric motor connected to a gear wheel 21. This sleeve carries at its lower end a disc 22 and a member 23 having a number of blades or paddles. In use, the paddle member 23 stirs and mixes the glass above the aperture B, and the disc 22 prevents the formation of a depression in the glass over the stem 9. The glass flows over the cone 11 to form a tube, and the rate of flow of the glass can be regulated by adjusting the position of the former 11 in relation to the aperture. Air is blown through the stem 9 to maintain the bore of the glass tube, and the inclination of the passage 11a causes the air to have a whirling motion as it enters the glass tube. The stem 9 can be rotated in order to expose the glass on the former 11 evenly to the heat from the burners below the aperture, and the whirling action of the air maintains the rotation of the glass after it leaves the former. The glass tube is drawn away in an horizontal direction by drawing-apparatus which comprises a number of pulleys 26, Fig. 7, having grooved rims in which the tube rests, and discs 27 which press the tube into the grooving. These discs 27 are rotated in unison with the pulleys 26, but the plane of each disc is inclined to that of the coacting pulley, as shown in Fig. 8. The inclination causes the glass tube to rotate as it is drawn forwards. After leaving the drawing-apparatus, the glass tube is cut into lengths by suitable mechanism, and the lengths are separated from one another by a belt conveyer which is driven at a greater speed than the tubing. The conveyer delivers the lengths of tubing into an incline down which they roll. The tubes cool and become straightened while they are rolling down the incline.