Abstract: A method for making a float glass convertible into a glass ceramic, by which a largely crystal fault-free glass can be produced. In this method the glass is cooled from a temperature (TKGmax), at which a crystal growth rate is at a maximum value (KGmax), to another temperature (TUEG), at which practically no more crystal growth occurs, with a cooling rate, KR, in ° C. min?1 according to: KR UEG KG max ? ? ? ? ? T UEG KG max 100 · KG max , wherein ?T=TKGmax?TUEG, and KGmax=maximum crystal growth rate in ?m min?1. The float glass has a thickness below an equilibrium thickness, a net width of at least 1 m and has no more than 50 crystals with a size of more than 50 ?m, especially no crystals with a size of more than 10 ?m, per kilogram of glass within the net width.

Abstract: A float tank comprise a lower chamber for containing a molten metal adapted to support a glass ribbon for producing a glass by a float forming process, wherein the float tank contains a first atmosphere generally above at least a portion of the glass ribbon and generally not above the molten metal, and a second atmosphere generally above the molten metal and not above the glass ribbon, wherein the first atmosphere differs in composition from the second atmosphere.

Abstract: The method of supporting and transporting hot flat glass on a gas bed for ceramicizing includes arranging a number of spaced-apart porous or perforated planar segments to form a base with a gas-permeable support surface so that slits, which are narrower than the planar segments, are formed between them, forcing gas through the porous or perforated planar segments and conducting the gas away through the slits between them so as to form the gas bed with no static pressure zones and with a parabolic pressure distribution and producing a predetermined temperature profile for ceramicizing through which the hot flat glass is transported on the gas bed without deformation and without any contact between it and the base. The resulting glass ceramic has smoother surfaces without pits or deformations.

Abstract: The invention concerns a device for supporting a horizontal guided, continuous glass strand; with a number of supporting blocks, which each exhibits a supporting area, facing the glass strand; the individual supporting block in the area of the supporting area is made from a porous, gas-impermeable diaphragm body; the diaphragm body is connected to a source of compressed gas for conveying gas through the supporting area.

Abstract: The invention relates to glass tubes for technical applications, especially for electrical or magnetic components, such as reed switches for example. According to a first embodiment, the glass tube has an inner bore (23) and at least one cross-sectional constriction (X) whereby the relationship applicable between the respective cross-sectional constriction (X) and the diameter (d) of the circumference of inner bore (23) is: x greater than or equal to 0.02*d, more preferably x greater than or equal to 0.1*d. According to a further embodiment, the glass tube has at least one inner bore with at least one inner edge, wherein the radius of curvature of the respective inner edge is less than or equal to 0.1 mm and preferably less than or equal to 0.03 mm. The glass tube is used as a preform for a subsequent redrawing process. The preform is formed by casting a molten glass into a shaft in the interior of which is located a shaping means for defining the inner bore.

Abstract: The thin flat glass substrate, especially for display engineering, has a thickness of less than 1.5 mm, a length of at least 1800 mm, a width of at least 1800 mm and a difference between a smallest thickness and largest thickness of less than 50 ?m. The float glass process for making the improved flat glass substrate provides flags (9) in the molten metal bath in the hot-spread region on both sides of the forming glass sheet, to minimize the variation in thickness of the thin flat glass substrate formed by the process.

Abstract: The invention relates to a method and an apparatus for producing optical glass elements, in particular optical prisms or optical rod lenses, using a drawing process. The geometry of the glass strand which is to be produced is controlled by means of cooling or heating elements positioned at least around portions of the periphery or longitudinal axis of the glass strand, inside or outside the heating apparatus.

Abstract: A roller table for supporting and transporting a hot glass strand. A plurality of rollers arranged parallel to each other and perpendicular to the transport direction of the glass strand are capable of being selectively rotated in the direction of transport of the glass strand. At least some of the rollers are sleeves, the casings of which are which are gas-permeable on at least a portion of their surfaces and the casings are provided with a supply of pressurized gas which is emitted through the openings of the gas-permeable surfaces.

Abstract: A method for making flat glass of good quality by rolling is described, in which a gas cushion is formed between the upper shaping roller and the glass sheet and contact between the lower shaping roller and the glass sheet is limited to a width of from 5 to 30 mm. The resulting flat glass has an upper surface quality that is nearly that of a fire-polished glass surface, while the lower surface has an improved quality that is better than that obtained by the prior art method. Furthermore it is advantageous that the method does not require an increase in the length of the cooling path following the rollers.

Abstract: The invention includes a method and an arrangement for influencing the flow of glass melts in a controlled way during the transfer from the melting furnace to a processing process. The simultaneous generation of electric and magnetic fields generates a force in the glass melt which boosts or inhibits the melt flow and acts substantially in the same direction as or in the opposite direction to the main direction of flow. It is in this way possible to control the melt flow without affecting the temperature of the melt. Consequently, the invention is suitable in particular for the accurately controllable feeding of a homogeneous glass melt to a glass production process.

Abstract: A device for manufacturing glass gobs includes a membrane body of a porous gas transmitting material. Channels for introducing compressed gas into the membrane body extend through the membrane body material and are spaced at a distance from the gas outlet surface of the membrane body. The channels run parallel to or are at an acute angle to the outlet surface. In an alternate embodiment, the channels are open channels at the opposite surface from the outlet surface.

Abstract: The invention relates to a method and device for non-contact moulding of fused glass or glass ceramic gobs by means of gas levitation, comprising the following method steps: a pre-form is generated, the pre-form is brought close to a moulding tool, which may be connected to a compressed gas source on the open-pored region thereof facing the pre-form in order to generate a gas cushion between the moulding tool and the pre-form and the moulding tool is directly heated at least during a part of the moulding phase.

Abstract: The invention relates to a method for the hot shaping of molten gobs on a mold base by interposing a gas bed, comprising the following method steps. According to the invention such a method comprises the following method steps: a mold base made of open-pore mold material is produced; the supporting surface of the mold base is coated permanently with a glass contact material; such a coating material is chosen or the coating is arranged in such a way that the layer comprises open pores after its application which allow a gas-conductive connection between the lower side and the upper side of the layer; the mold base is charged with a gas in order to produce a gas bed on the upper side of the layer.

Abstract: The apparatus for supporting a glass body is made by a method including the following steps: putting carbon-containing fibers in an axially parallel arrangement and tightly packing them; twisting the resulting tightly packed carbon-containing fiber bundle to form a carbon-containing fiber rope piece and fixing it in a twisted state; then pyrolyzing the resulting carbon-containing fiber rope piece, soaking the pyrolyzed carbon-containing fiber rope piece in a silicon-containing fluid and ceramicizing the carbon-containing fiber rope piece. The supporting apparatus formed by this method includes a gas-permeable body, which has channels or passages through which a gas, such as air, can pass. The channels are inclined at their outlet ends on a gas outlet surface of the gas-permeable body.

Abstract: The invention relates to a method for heating up and shaping a preform consisting of glass or glass ceramic. According to the invention, a preform, formed using conventional methods, is heated to a temperature that is below the adhesion temperature of the gas, i.e. to below critical viscosity; in a second heating phase the preform is put into a hovering state through the supply of levitation gas; in the hovering state the preform is heated by a microwave heating apparatus to a temperature that permits its shaping; and the preform is delivered to a shaping station.

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 method for the hot shaping of molten gobs on a mold base by interposing a gas bed, comprising the following method steps. According to the invention such a method comprises the following method steps: a mold base made of open-pore mold material is produced; the supporting surface of the mold base is coated permanently with a glass contact material; such a coating material is chosen or the coating is arranged in such a way that the layer comprises open pores after its application which allow a gas-conductive connection between the lower side and the upper side of the layer; the mold base is charged with a gas in order to produce a gas bed on the upper side of the layer.

Abstract: The method of making globular or spherical bodies of optical quality includes filling receptacles (2) in a heat-resistant support (3) made of a porous material with glass gobs (1); conducting gas through the heat-resistant support so that a gas flow (4) passes through the support in a direction (14) opposite to a direction in which gravity acts; heating the heat-resistant support (3) to a temperature at which the glass gobs (1) have a viscosity of up to about 106 poise; maintaining the support (3) at this temperature for a predetermined time interval; and then cooling the support (3) to ambient temperature while continuing to provide the gas flow (4) through the support (3).

Abstract: The present invention relates to a process for ceramising glass ceramics (so-called green glass). The process according to the present invention comprises the following procedural steps: green glass (3) is manufactured; the green glass is placed in a suspended state on a levitation substrate by supply of levitation gas; the green glass is heated in the suspended state by IR radiation until such time as the desired ceramising has set in.

Abstract: An method and apparatus for shaping a floor of a glass vessel including a source of pressurized gas, a pressure-sealed housing in fluid communication with the source of pressurized gas and a mold at least partially within the pressure-sealed housing. The mold includes a shaping floor with a first side subjected to the source of pressurized gas.