Abstract: The present invention relates to a device and method for transporting, homogenizing or conditioning of glass melts or glass ceramic melts and is distinguished in that the new formation of bubbles after refining is at least reduced. The new formation of bubbles on the surfaces of components that are in contact with the melt is at least reduced by means of a layer having iridium as a material.

Abstract: The invention relates to a method and apparatus for the production of high-melting glass materials or high-melting glass ceramic materials by a process during which a temperature of a molten mass exceeds 1,760° C., wherein a shard material or raw material is molten to a molten mass, the molten mass is fined, and the molten mass emerges via a tubular outlet made of iridium or an iridium alloy having an iridium content of at least 50 wt.-%. According to the invention the temperature of a section of said tubular outlet, which is in contact with the ambient atmosphere having a natural gas composition, is controlled or regulated such that said temperature is held below 1,000° C. except during pouring out the molten mass out of said tubular outlet. Thus, an oxidative decomposition of the apparatus can be prevented.

Abstract: The invention relates to novel uses of glass ceramics, wherein glass ceramics, in particular, in the form of a glass ceramic tube, are used. Said glass ceramics contain 0—less than 4 wt % P205 and 0 less than 8 wt-% CaO. The tubes can be used in multiple areas of application and/or in multiple types of lamps, for example in general lighting or car lights and in heat radiators, such as halogen lamps or incandescent lamps, and/or in high pressure discharge lamps or low pressure discharge lamps. The glass ceramics, can also, in particular, be minimised in order to form known backlighting in conjunction with background lighting of flat screens. Said type of glass ceramics have excellent spectral transmission in the visible wave length rang and are solarisation stable and absorb strong UV light.

Abstract: A process for shaping a body with elongate structures on its surface, bodies produced using the process, and to apparatuses having these bodies are provided. For this purpose, a preform is provided, at the surface, with structures which are elongate along one direction, the preform is heated at least in one region and the preform is drawn in the heated state until at least part of the preform has adopted a cross section which substantially corresponds to the desired cross-sectional shape or final cross-sectional shape. The preform is heated by means of radiation which has a spectral distribution which is such that at most half of the radiation power is absorbed during a single pass through the material.

Abstract: The double crucible for a glass drawing method has a heatable outer crucible (1) and an inner crucible (2) surrounded by the outer crucible (1), which is heatable separately from the outer crucible (1). Both crucibles (1,2) have an outlet nozzle (1a, 2a) for the glass to be drawn. To make glass fibers from heavy metal oxide glass (HMO-glass) with higher quality and comparatively simple crucible features, the outlet nozzle (1a) of the outer crucible (1) extends a certain distance beyond the outlet nozzle (2a) of the inner crucible (2). Surfaces of the outlet nozzles coming in contact with the glass melt are polished and are provided on a material, which has a reducing action on heavy metal glass in the melt in all cases. These surfaces also have sufficient mechanical strength for and chemical inertness to heavy metal oxide glass.

Abstract: Zinc-containing optical glass materials with a refractive index nd between 1.52 and 1.66, an Abbe number ?d of between 35 and 54 and a composition (in % by weight based on oxide) of: SiO2 38–58, ZnO 0.3–42, PbO 0–<30, ZnO+PbO 20–55, Li2O 0–<3, Na2O 0–14, K2O 0–12, Li2O+Na2O+K2O ?2, F 0–3, MgO 0–6, CaO 0–<5, SrO 0–6, BaO 0–<0.9, B2O3 0–<1, Al2O3 0–<1.5 and ZrO2 0–<2 and, if appropriate, refining agents in the customary amounts.

Abstract: The invention relates to a device and a process for producing a glass tube, preferably continuously. The device comprises a shaft (9) into which a glass melt is introduced, so that the outer profile of the glass tube (1) is determined at least in sections by the shaft, and a shaping means (10), which extends coaxially in the interior of the shaft, for determining the inner profile of the glass tube (1). The shaping means (10) is cooled and the shaft is disposed vertically. The glass melt is cast freely into the shaft (9) while forming a free meniscus. According to the invention, the shaping means (10) is cooled so that the glass melt solidifies in the shaft to form the glass tube (1). The glass passes through the temperature range which is critical for crystal formation within a very short time, so that precise glass tubes can also be produced from readily crystallising glasses. It is also possible to precisely shape glass tubes with any desired inner and/or outer profiles.

Abstract: The invention relates to a device for the production of high-melting glass materials or high-melting glass ceramic materials, comprising a vessel for accommodating molten glass and a container that accommodates the vessel, whereby the vessel has a tubular outlet. According to the invention, the device is characterised by the fact that the vessel and a first section of the tubular outlet if formed of iridium or a material with a high iridium content, whereby the container is designed to accommodate the vessel and the first section of the tubular outlet under a protective gas atmosphere. The invention also relates to a corresponding method. The molten glass is shaped into a formed part in a discontinuous operation. The choice of the material for the vessel used as the crucible allows the attainment of high temperatures according to the invention which enables glass materials or glass ceramic materials with a much higher spectral transmission in the visible wavelength range.

Abstract: There is now provided a method and a device for the control and setting of the redox state of redox fining agents in a glass melt, in which method, during the melting process, essentially oxygen gas is blown through the glass melt.

Abstract: Zinc-containing optical glass materials with a refractive index nd between 1.52 and 1.66, an Abbe number ?d of between 35 and 54 and a composition (in % by weight based on oxide) of: SiO2 38-58, ZnO 0.3-42, PbO 0-<30, ZnO+PbO 20-55, Li2O 0-<3, Na2O 0-14, K2O 0-12, Li2O+Na2O+K2O ?2, F 0-3, MgO 0-6, CaO 0-<5, SrO 0-6, BaO 0-<0.9, B2O3 0-<1, Al2O3 0-<1.5 and ZrO2 0-<2 and, if appropriate, refining agents in the customary amounts.

Abstract: A method and device for nozzle-injection of gas into molten glass is disclosed wherein a gas stream is introduced into the molten glass in a temporally pulsed throughput such that the gas stream is interrupted between two sequential pulses, the duration of each pulse amounting to less than one second.

Abstract: The invention relates to a process for shaping a body with elongate structures on its surface, to bodies produced using the process and to apparatuses comprising bodies of this type, in order to enable spacers to be produced with a high degree of lateral positioning accuracy, in large numbers and at low cost with a process of this type. For this purpose, a preform is provided, at the surface (13), with structures (2-11, 2A, 11A, 2B) which are elongate along one direction, the preform which has been provided with the structures is heated at least in one region (14) and the preform is drawn in the heated state until at least part of the preform has adopted a cross section which substantially corresponds to the desired cross-sectional shape or final cross-sectional shape. The preform is heated by means of radiation which has a spectral distribution which is such that at most half of the radiation power is absorbed during a single pass through the material.

Abstract: Zinc-containing optical glass materials with a refractive index nd between 1.52 and 1.66, an Abbe number vd of between 35 and 54 and a composition (in % by weight based on oxide) of: SiO2 38-58, ZnO 0.3-42, PbO 0-<30, ZnO+PbO 20-55, Li2O 0-<3, Na2O 0-14, K2O 0-12, Li2O+Na2O+K2O≧2, F 0-3, MgO 0-6, CaO 0-<5, SrO 0-6, BaO 0-<0.9, B2O3 0-<1, Al2O3 0-<1.5 and ZrO2 0-<2 and, if appropriate, refining agents in the customary amounts.

Abstract: A process for the remelting of glass bars, including the steps of introducing a glass bar into an upper end of a receiving shell; providing a molten bath having a surface underneath the receiving-shell; positioning the receiving shell such that a lower edge of the receiving shell is located at the height of the surface or above it; heating a lower end of the glass bar to a temperature above a softening temperature of the glass, resulting in a melt-off process at the lower end of the glass bar to produce a melt stream; controlling the melt-off process such that the melt stream continuously enters the molten bath proximate the surface with avoidance of a constriction; and drawing off melt from the molten bath by means of an arrangement for drop generation.

Abstract: The invention relates to a device for purifying molten glass;

Abstract: There is now provided a method and a device for the control and setting of the redox state of redox fining agents in a glass melt, in which method, during the melting process, essentially oxygen gas is blown through the glass melt.

Abstract: The invention relates to a method and a device for nozzle-injection of gas into molten glass.

Abstract: The invention relates to a device for the remelting of glass bars:

Abstract: A transparent or translucent inorganic material, especially a glass-ceramic and/or composite material, is provided with a low average thermal longitudinal expansion coefficient, .alpha., of from -1.times.10.sup.-6 K.sup.-1 to +2.times.10.sup.-6 K.sup.-1 in the temperature range of -50.degree.-700.degree. C., with the following composition (in weight percent):Li.sub.2 O, 2.5-6.0; Na.sub.2 O, 0-4.0; K.sub.2 O, 0-4.0; Na.sub.2 O+K.sub.2 O, 0.2-4.0; MgO, 0-3.0; ZnO, 0-3.0; BaO, 0-3.5; CaO, 0-1.0; SrO, 0-1.0; Al.sub.2 O.sub.3, 18-28; SiO.sub.2, 50-70; TiO.sub.2, 1.0-7.0; ZrO.sub.2, 0-3.5; TiO.sub.2 +ZrO.sub.2, 1.0-7.0; and P.sub.2 O.sub.5, 0-8.0,optionally with coloring components (in weight percent):V.sub.2 O.sub.5, 0-2.0; Cr.sub.2 O.sub.3, 0-2.0; MnO, 0-2.0; Fe.sub.2 O.sub.3, 0-2.0; CoO, 0-2.0; and NiO, 0-2.0,optionally, conventional refining agents, such as As.sub.2 O.sub.3, Sb.sub.2 O.sub.3, NaCl, and Ce.sub.2 O.sub.