Abstract: The present invention relates to a high-purity bioactive glass, having the following composition in % by weight: SiO2 ??35-86 Na2O ?5.5-35 CaO ??4-46 P2O5 ??1-15 Further additional 0.05-15 substances and to a process for producing it, in which the glass is produced in a radiofrequency-heated skull crucible.

Abstract: In order, inter alia, to provide an apparatus and a process for melting inorganic substances which allow a high product quality to be obtained and the technological outlay to be reduced, the invention provides a process and an apparatus in which the volumetric ratios between a melting region and a refining region can be flexibly adapted.

Abstract: The invention describes a method and an apparatus for the rapid melting of in particular high-purity, aggressive and/or high-melting glasses in a skull crucible, in which high-frequency energy is introduced into the contents of the crucible by means of a coil arrangement surrounding the skull crucible, in order to heat the melt, and the batch is laid and the molten glass discharged in the upper region of the crucible, and undissolved constituents of the batch are retained by means of a cooled bridge which is immersed in the melt. According to the invention, the glass is taken off above the coil arrangement (1.3) and is fed for further processing without flowing through the coil region. This has the advantage that simple, conventional components can be used to connect the melting unit to the further-processing stations, and the type of connection can be selected in such a way that it is possible to prevent the quality of the glass from being impaired by connection techniques which are less than optimum.

Abstract: The invention relates to a method for changing glass compositions in continuously operated melting installations which has a significantly shortened melt changeover time and therefore lower costs and in which the glass quality is not adversely affected.

Abstract: An apparatus and a method for low-contamination melting of high-purity, aggressive and/or high-melting glass or glass-ceramic are provided. For this purpose, a melt is heated in a crucible or melting skull crucible by means of high-frequency radiation and is mixed or homogenized in the melting crucible. A gas nozzle, from which gas bubbles, e.g. oxygen bubbles (known as O2 bubbling), escape into the melt, is provided at the base of the crucible.

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: The invention relates to a structural component for a device for the treatment of melts, especially of glass melts;