Abstract: A glass element has, per kg of glass, 50 or fewer inclusions having a size of 2 ?m to 10 ?m. The glass element can be made of borosilicate glass.

Abstract: An apparatus and a method for producing glass products from a glass melt, avoiding bubble formation, are disclosed, wherein the apparatus includes a crucible and an internally component for processing the glass melt, and wherein, for heating the glass melt, the apparatus comprises an AC generator which energizes the crucible or stirring crucible via electrical connection elements. The component or stirring system is connected via a current-limiting choke having a variable impedance with the power supply elements. The impedance of the current-limiting choke is adjusted so that a AC density existing in the glass melt lies between a lower limit value and an upper limit value. By means of a choke and by adjusting the impedance it can be achieved that the AC load of the system can be minimized and that simultaneously the water decomposition reaction at the precious metal surfaces can positively be influenced.

Abstract: An apparatus and a method for producing glass products from a glass melt, avoiding bubble formation, are disclosed, wherein the apparatus includes a crucible and an internally component for processing the glass melt, and wherein, for heating the glass melt, the apparatus comprises an AC generator which energizes the crucible or stirring crucible via electrical connection elements. The component or stirring system is connected via a current-limiting choke having a variable impedance with the power supply elements. The impedance of the current-limiting choke is adjusted so that a AC density existing in the glass melt lies between a lower limit value and an upper limit value. By means of a choke and by adjusting the impedance it can be achieved that the AC load of the system can be minimized and that simultaneously the water decomposition reaction at the precious metal surfaces can positively be influenced.

Abstract: A melting and/or refining unit for conductively heatable melts, in particular glass melts, is provided. The melting and/or refining unit has a tank and at least one electrode. The electrode passes through an opening in a wall of the tank so as to be immersed in the conductively heatable melt. The melting and/or refining unit has an apparatus for reducing the local introduction of heating power into at least one region adjacent to the electrode.

Abstract: The float glass apparatus has a glass melt producing unit including a melting tank and a refining tank for the glass melt, a float tank including a metallic basin and metal bath contained in the basin, conducting devices for conducting the glass melt from the glass melt producing unit to the metal bath and auxiliary devices as needed. In order to minimize bubble defects and extend service life of apparatus parts made from platinum or a platinum alloy, the apparatus includes a device for minimizing direct current flowing between the glass melt producing unit and the float tank, which includes an auxiliary electrode connected with ground and located in the glass melt producing unit in electrical contact with the glass melt and a direct electrical connection between the metallic basin of the float tank and ground.

Abstract: The float glass apparatus has a glass melt producing unit including a melting tank and a refining tank for the glass melt, a float tank including a metallic basin and metal bath contained in the basin, conducting devices for conducting the glass melt from the glass melt producing unit to the metal bath and auxiliary devices as needed. In order to minimize bubble defects and extend service life of apparatus parts made from platinum or a platinum alloy, the apparatus includes a device for minimizing direct current flowing between the glass melt producing unit and the float tank, which includes an auxiliary electrode connected with ground and located in the glass melt producing unit in electrical contact with the glass melt and a direct electrical connection between the metallic basin of the float tank and ground.

Abstract: The apparatus for reduced-pressure refining of a glass melt includes a refining bank formed so that a reduced pressure is generated by a glass flow in it. The refining bank has a component, which is made from a refractory metal or refractory alloy acting as glass-contact material. The refractory metal or alloy contains molybdenum, tungsten, tantalum, and/or hafnium. The device of the present invention includes a protective gas reservoir for a protective gas and an automatically operating valve connecting the reservoir with the refining bank so that an inner side of the component that would otherwise be exposed when a pressure rise or a falling glass melt column occurs is protected from oxidation by the protective gas. A process for using the device during refining of the glass melt is also part of the invention.

Abstract: To reduce the risk of damage to the refractory material, in particular caused by the formation of cracks and corrosion, the invention provides a unit, in particular a melting and/or refining unit and/or a distributor system and/or a channel system, for conductively heatable melts (30), in particular glass melts, which has a tank and at least one electrode (20), the electrode (20) passing through an opening in a wall (10) of the tank so as to be immersed in the conductively heatable melt (30), wherein the unit has an apparatus for reducing the local introduction of heating power into at least one region—adjacent to the electrode (20)—of the wall (10).

Abstract: The suction feeder for glass processing includes a housing containing a material; a heatable noble metal or noble metal alloy feed line embedded in the housing in a thermally insulated fashion; a connection element at one end of the feed line for connection with a molten glass supply device and an outlet element for operative engagement with a suction device at the other end of the feed line. To prevent aspiration of bubbles through the feed line the material together with the housing surrounds the heatable feed line and has a composition and/or structure such that in operation a negative pressure can be produced on an outer side of the feed line. Preferably this negative pressure is lower than a minimum internal pressure within the feed line that is established during a suction process.

Abstract: The invention concerns a process and a device from the production of molten glass. According to the invention, measures will be taken to lead the current of the molten glass through the tank furnace so that cutoffs of the glass current between the surface of the glass bath, on the one hand, and the outlet opening on the other hand are avoided and a an equal holding period of all melt particles in the tank furnace is achieved.

Abstract: The invention concerns a process and a device from the production of molten glass. According to the invention, measures will be taken to lead the current of the molten glass through the tank furnace so that cutoffs of the glass current between the surface of the glass bath, on the one hand, and the outlet opening on the other hand are avoided and a an equal holding period of all melt particles in the tank furnace is achieved.

Abstract: In the method of making glass a glass melt is formed from starting materials in a melt apparatus, which includes at least one metal part having a metal surface in contact with the glass melt in a first region of the glass melt having a predetermined oxygen partial pressure. This method includes suppressing oxygen bubble formation in the glass melt at a contacting surface between the metal surface and the glass melt; immersing an electrode in a second region of the glass melt not including the first region, which has a lower oxygen partial pressure than in the first region, and electrically conductively connecting the electrode and the at least one metal part. An apparatus for performing the method is also described as well as glasses made by the method.

Abstract: A float glass apparatus typically includes a float tank for a metal bath, the metal bath, a glass melt producing unit, which includes a melting tank for making a glass melt and a refining, tank for degassing the glass melt, and conducting devices for conducting the glass melt from the glass melt producing unit to the metal bath of the float tank and auxiliary devices as needed. In order to minimize bubble defects and extend service life of Pt units by a suitable electrical device the float tank with the metal bath is connected electrically with ground and at least one auxiliary electrode is connected with ground and put in electrical contact with the glass melt in the melting tank.

Abstract: The invention relates to a method and a device for refining a glass melt, using negative-pressure apparatus. According to the invention, the glass melt is fed to a refining bench by means of an uptake pipe and is discharged from the refining bench by means of a downpipe, a negative pressure being created over the flow of glass in the refining bench. The invention is characterised in that the uptake pipe and/or the downpipe and/or the refining bench has/have at least one component consisting of at least one refractory metal and/or of a refractory metal alloy as the glass contact material.

Abstract: An apparatus for making glass in which a glass melt is refined in a vessel with oxygen is described. It includes a melt-containing vessel (10) having a refining region (3) for refinement of the glass melt and a noble metal member for producing oxygen in the melt. The noble metal member (40) has an outer side facing the glass melt and an inner side facing away from the glass melt washed with and acted on with oxygen. Oxygen-containing bubbles are vigorously generated on the outer side of the noble metal member facing the glass melt when the inner side is washed with the oxygen.

Abstract: An apparatus for making glass in which a glass melt is refined in a vessel with oxygen is described. It includes a melt-containing vessel (10) having a refining region (3) for refinement of the glass melt and a noble metal member for producing oxygen in the melt. The noble metal member (40) has an outer side facing the glass melt and an inner side facing away from the glass melt washed with and acted on with oxygen. Oxygen-containing bubbles are vigorously generated on the outer side of the noble metal member facing the glass melt when the inner side is washed with the oxygen.

Abstract: The invention relates to a device for the production of a glass melt from a batch; with a melt tank (1) that has peripheral walls (1.1-1.4) and a bottom (1.5); with a discharge channel (2) which is located under the bottom (1.5) of the melt tank (1) and which is in conducting connection with the melt bath (3) over an entry opening (2.3) and has an outlet opening (2.4) for the finished melt in the zone of a peripheral wall (1.1) of the melt tank (1); with at least one heating arrangement for the heating of the melt bath (3); the entry opening (2.3) of the discharge channel (2) is arranged in a central zone of the bottom (1.5) of the melt tank (1); the discharge channel (2) has a covering (2.2) which is located at least approximately at the level of the bottom (1.5) of the melt tank (1).

Abstract: An apparatus for making glass in which a glass melt is refined in a vessel with oxygen is described. It includes a melt-containing vessel (10) having a refining region (3) for refinement of the glass melt and a noble metal member for producing oxygen in the melt. The noble metal member (40) has an outer side facing the glass melt and an inner side facing away from the glass melt washed with and acted on with oxygen. Oxygen-containing bubbles are vigorously generated on the outer side of the noble metal member facing the glass melt when the inner side is washed with the oxygen.

Abstract: Suction feeders of this type are used in the processing of glass and have a heatable feed line (1) consisting of noble metal. Said feed line is embedded in a heat-insulated manner in a housing (4a) with a refractory material (3a). Said housing has a connecting flange (5) for connection to a molten glass supply device and an exit flange (6) for operational engagement with a suction ball (7) which removes the gob from the feed line (1). According to the invention, the material (3a, 4a) surrounding the feed line (1) is configured in such a way in terms of the construction and/or substance that a negative pressure can be produced on the outer periphery of the feed line (1), so that the mechanical compression of the feed line (1) is minimised and air bubbles are not drawn up.

Abstract: According to the invention, measures will be taken to lead the current of the molten glass through the tank furnace so that cutoffs of the glass current between the surface of the glass bath, on the one hand, and the outlet opening on the other hand are avoided and a an equal holding period of all melt particles in the tank furnace is achieved.