Kernforschungszentrum Karlsruhe Gmbh

Gesellschaft Fur Kernforschung M.b.h.

Hartmut Seiffert

Siegfried Weisenburger

Herbert Koschorke

Friedrich Kaufmann

Wolfgang Grunewald

Karl-Heinz Weiss

Dieter Sienel

Fred Holl

A discharging device is provided at the bottom of a glass melting furnace. The device includes an inductively heated outlet unit including a compression flange having an inlet opening and an outlet pipe extending from the compression flange to form therewith a unit having a T-shaped cross section. The outlet pipe is penetrated by an outlet channel communicating with the inlet opening. The outlet pipe projects downwardly out of an opening in the furnace. An outlet block is seated on the compression flange and has an outlet channel flush with the inlet opening of the compression flange. An annular supporting flange supports the outlet unit from the bottom against the compression flange, with the annular supporting flange being supported by a bottom carrier plate of the furnace and the outlet pipe of the outlet unit projecting through an opening in the annular supporting flange. A thermal and mechanically deflecting creep barrier is disposed for stopping creep flow of glass melt between the compression flange of the outlet unit and other components of the furnace, including the outlet block, in contact with the compression flange, by freezing the melt and causing a pressure loss in the creep flow with respect to static pressure of the melt in the furnace.

Discharging device for a glass melting furnace

A bottom outlet device is provided for a glass melting furnace, with heating of a glass melt being effected to within the temperature range of the electrical conductivity of the melt by way of electrodes disposed in the interior of the furnace and projecting into the melt. An inductively heatable and metallic outlet unit projects from the bottom of the furnace and includes an outlet opening and an interior outlet channel communicating with the outlet opening. An outlet block comprised of ceramic bricks is disposed above the outlet unit and includes a throughgoing channel which opens toward the interior of the furnace and which is flush with the interior outlet channel of the outlet unit. A bottom electrode comprised of metal is disposed at a lowermost portion of the interior of the furnace. The bottom electrode is penetrated by a further channel which is flush with the throughgoing channel in the outlet block and is thereby in communication with the outlet opening of the outlet unit.

Bottom outlet device for a glass melting furnace

A method and apparatus for periodically discharging batches of a glass melt from a ceramic glass melting furnace in which localized heating energy limitable in time is supplied to the glass melt by means of electrodes in the furnace, the furnace being provided at its bottom with an induction heatable outlet member of ceramic material presenting a vertically oriented outlet passage for discharge of such batches, the furnace being operated to cause the outlet passage to be closed by a plug of the glass when no discharge is to take place, in which such plug is melted for discharging a batch of the glass melt via the outlet passage by preheating the outlet member and the glass plug by induction heating up to a preheating temperature which is below the melting temperature of the glass and above which the rate of increase of the electrical conductivity of the glass plug as a function of increasing temperature is greater than that of the ceramic material of the outlet member, and then further heating the plug, while retaining the induction heating power by means of resistance heating in which only the glass plug and the melt in the furnace serve as resistances, until the plug becomes almost liquid and molten and is suddenly pushed out of the outlet passage by the hydrostatic pressure of the glass melt thereabove.

Method and apparatus for discharging glass from a melting furnace

Method and device for effecting radioactive offgas filtration by means of a mass of filter material, and filter material regeneration, at temperatures in excess of 500.degree. C. in which substances to be filtered impinge on the filter material mass in at least one direction, filtration being effected by removing a layer of contaminated filter material in the direction opposed to the direction in which substances impinge on the filter material in order to remove the filtered substances for filter cleaning. Removal of the contaminated filter material is carried out by adding a fluxing agent to the filter material at operating temperatures for regenerating the filter material by means of a cleanup melt. This fluxing agent may be a glass frit, an alkali hydroxide or an alkali or alkaline earth metal salt.

Method of radioactive offgas filtration and filter regeneration and

Method for the solidification, in a manner which protects the environment against contamination, of waste materials obtained during reprocessing of irradiated nuclear fuel and/or breeder materials in a matrix of borosilicate glass. Highly radioactive solutions or slurries containing the waste materials in dissolved or suspended form are evaporated in a vessel in the presence of glass former substances until they are dry, the dry residue is calcinated and the calcinate is melted together with the glass formers while the waste gases are discharged to the environment. The waste liquid is obtained from a reprocessing system without pretreatment, is mixed with glass formers and a reduction agent and then is introduced in a controlled, continuous manner into the center of a borosilicate glass melt disposed in a melting crucible at a temperature in the region of 1000.degree. to 1400.degree. C. to form an island-like drying and calcinating zone on the surface of the melt while avoiding contact of the waste liquid with the walls of the crucible. A reducing atmosphere is formed and the presence of components in the waste gas which would radiologically and/or chemically contaminate the environment are substantially avoided.

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Karlsruhe, Germany

Hartmut Seiffert