Controlling the temperature during the production of glass tubes in Vello and down-draw methods, comprises transferring glass melt into glass-tube needle cell, dosing the melt by nozzle ring on dosing draw needle, and heating the needle

摘要

The method comprises transferring a glass melt (3) into a glass-tube needle cell (1) and dosing the melt by a nozzle ring (4) on a dosing draw needle (5), and heating the nozzle and the draw needle with their conical glass tube molded body (7). The wall of the nozzle and draw needle consists of electrically conductive material and the heating takes place by current flow in the electrically conductive wall material. A double-walled pipe material is used for the dosing drawing needle. An inner wall and outer wall of the double-walled pipe are electrically connected with one another at an end. The method comprises transferring a glass melt (3) into a glass-tube needle cell (1) and dosing the melt by a nozzle ring (4) on a dosing draw needle (5), and heating the nozzle and the draw needle with their conical glass tube molded body (7). The wall of the nozzle and draw needle consists of electrically conductive material and the heating takes place by current flow in the electrically conductive wall material. A double-walled pipe material is used for the dosing drawing needle. An inner wall and outer wall of the double-walled pipe are electrically connected with one another at an end, are separated by an insulation layer, and are connected at the other end of the pipe with separate power supply connections (8, 9) so that interior and external wall are configured in a series connection of a filament current. An electrical resistance of the nozzle and draw needle is used as parameter for adjustment the heating power. An independent claim is included for a device for controlling the temperature during the production of glass tubes in Vello and down-draw methods.