Verfahren und Vorrichtung zur kontinuierlichen Behandlung von zu verfestigenden Gegenstaenden aus Glas oder glaskristallinem Material in Salzschmelzen

摘要

1356630 Producing glass tubes KOMBINAT TECHNISCHES GLASS ILMENAU VEB 7 July 1971 31850/71 Heading C1M Glass tubes are continuously formed from glass forming material by casting the material on to one end of a rotationally symmetrical internal surface formed by rotating a liquid layer immiscible with said material, the material before or after casting being heated to the required viscosity and the material after casting being caused to slide along the liquid surface and its viscocity increased by cooling whereby the completed tube may be withdrawn from the other end of the surface. During rotation of the liquid layer some liquid is withdrawn from the layer, treated (e.g. purified) and subsequently returned to the rotating layer. The method may be carried out by casting molten glass on a liquid layer 2 contained in a rotating drum 1 inclined at a small angle to the horizontal and having inwardly projecting ribs 32 to transmit rotation to the liquid. The drum has at each end shields 8 and outside shield collectors 12, 121 provided with means for introducing and maintaining a protective gas. Solid material may be cast on to the liquid in which case a centrally located electrical heater is provided within the drum to melt the material (Fig. 2, not shown). The solid material may be cast on to a first glass layer to provide a multi layered tube. The material may be such as to produce foam glass upon heating. In a modification molten glass is fed into the base of a vertical chamber in which the liquid is rotated by means of a stirrer or by a stator which produces a rotating magnetic field. The finished glass tube is continuously withdrawn upwardly. In each of the above processes the liquid may be one metal, e.g. tin, a metal alloy, e.g. tin and silver, a salt, metal oxide or a mixture thereof. The surface of the liquid may be protected from oxidation by a gas (e.g. a H 2 /N 2 mixture) or a layer of molten salt (e.g. NaCl/KCl mixture). During rotation the glass may be subject to an electric current to promote ion exchange between the liquid and glass.