Abstract: A glass-melting furnace, which suppresses the effect of exhaust gas on molten glass quality, a process for producing molten glass, and a process and apparatus for producing glass products. The glass-melting furnace containing: a raw glass material particle feed portion disposed downwardly at a furnace wall portion in an upper portion of the glass-melting furnace; a heating unit provided under the feed portion, which forms a gas phase portion for converting raw glass material particles into liquid glass particles; a flue inlet disposed on the upstream side of the gas phase portion in a flow direction of the molten glass liquid; a furnace-bottom portion, which accumulates the liquid glass particles that produce the molten glass liquid; and a discharge portion, which discharges the molten glass liquid.

Abstract: The present invention provides a process for producing a molten glass which can produce a molten glass having a good quality, a glass-melting furnace, a process for producing glass products and an apparatus for producing glass products. While an oxygen combustion burner 20 is rotated by a motor 38, glass raw material particles (not shown) are dropped into a high-temperature gas phase atmosphere produced by a flame F of the oxygen combustion burner 20, to be changed into liquid glass particles. By rotation of an outlet (nozzle) of the oxygen combustion burner 20, the falling position of the liquid glass particles 26, changes with time. Accordingly, generation of bubbles caused by continuous fall of the liquid glass particles in a particular position on a molten glass liquid surface is prevented. Accordingly, it is possible to produce a molten glass having a good quality with few bubbles.

Abstract: Glass raw material particles are dropped from an oxygen combustion burner 24, and the glass raw material particles are heated by a flame F of an oxygen combustion burner 24 and a thermal plasma P, to melt the particles. Liquid glass particles 30 produced by the melting fall downwardly in a melting tank 12, and fall on a surface of a molten glass liquid G in the melting tank 12. Then, an upper layer G1 of the molten glass liquid G is heated by electrodes 40, 40 of a heating apparatus 38 provided in the melting tank 12. By this method, air and residual gas generated in the molten glass liquid G and the liquid glass particles 30 fallen onto the surface of the molten glass liquid G, become bubbles, surface and are smoothly discharged.

Abstract: Objective of the present invention is to provide a glass melting furnace, a process for modifying a glass melt and a process for producing glass melt, whereby composition-modified glass melt containing an additive component at a high concentration can be produced with an excellent quality. The glass melting furnace 10 of the present invention is a glass melting furnace 10 for adding an additive to a molten state glass to form composition-modified glass melt, discharging the composition-modified glass melt, and a forehearth 20, said forehearth comprising a feed portion to feed an additive, and a heating means to form a heating gas phase portion above the liquid surface of the glass melt to convert the additive from the feed portion into melted particles of additive below the feed portion.

Abstract: Glass raw material particles are dropped from an oxygen combustion burner 24, and the glass raw material particles are heated by a flame F of an oxygen combustion burner 24 and a thermal plasma P, to melt the particles. Liquid glass particles 30 produced by the melting fall downwardly in a melting tank 12, and fall on a surface of a molten glass liquid G in the melting tank 12. Then, an upper layer G1 of the molten glass liquid G is heated by electrodes 40, 40 of a heating apparatus 38 provided in the melting tank 12. By this method, air and residual gas generated in the molten glass liquid G and the liquid glass particles 30 fallen onto the surface of the molten glass liquid G, become bubbles, surface and are smoothly discharged.

Abstract: A glass-melting furnace, which suppresses the effect of exhaust gas on molten glass quality, a process for producing molten glass, and a process and apparatus for producing glass products. The glass-melting furnace containing: a raw glass material particle feed portion disposed downwardly at a furnace wall portion in an upper portion of the glass-melting furnace; a heating unit provided under the feed portion, which forms a gas phase portion for converting raw glass material particles into liquid glass particles; a flue inlet disposed on the upstream side of the gas phase portion in a flow direction of the molten glass liquid; a furnace-bottom portion, which accumulates the liquid glass particles that produce the molten glass liquid; and a discharge portion, which discharges the molten glass liquid.

Abstract: An apparatus for producing molten glass, a process for producing molten glass, an apparatus for producing a glass product and a process for producing a glass product, which are capable of preventing deterioration of the quality of molten glass caused by deposition of scattered particles on a furnace wall or a flue. In the present invention, together with the operation of introducing and melting glass material particles by an oxygen combustion burner, glass cullet pieces are dropped from glass cullet pieces-introducing tubes to form a substantially cylindrical enclosure around a flame by a flow of glass cullet pieces. That is, glass cullet pieces are dropped from eight glass cullet pieces-introducing tubes to partition off the furnace wall from the flame. And, particles scattering from the flame are captured as deposits on the surface of falling glass cullet pieces and dropped into a glass melt in the melt reservoir.

Abstract: The present invention provides (i) a glass melting furnace, (ii) a process for producing molten glass, (iii) an apparatus for producing a glass product, and (iv) a process for producing a glass product, which are capable of preventing deterioration of the quality of molten glass caused by deposition of particles floating on a wall of the furnace. The melting furnace described herein includes a melting tank in which a flue located substantially at the center of a ceiling wall and a number of first heating units are disposed, such that particles floating in the furnace are suctioned off by a suction power of the flue and discharged from the furnace without being directed to a surrounding furnace wall. This drastically reduces the amount of floating particles deposited on the furnace wall, which prevents damage to the furnace wall and deterioration of the quality of glass produced therein.

Abstract: The present invention provides a process for producing a molten glass which can produce a molten glass having a good quality, a glass-melting furnace, a process for producing glass products and an apparatus for producing glass products. While an oxygen combustion burner 20 is rotated by a motor 38, glass raw material particles (not shown) are dropped into a high-temperature gas phase atmosphere produced by a flame F of the oxygen combustion burner 20, to be changed into liquid glass particles. By rotation of an outlet (nozzle) of the oxygen combustion burner 20, the falling position of the liquid glass particles 26, 26 . . . changes with time. Accordingly, generation of bubbles caused by continuous fall of the liquid glass particles in a particular position on a molten glass liquid surface is prevented. Accordingly, it is possible to produce a molten glass having a good quality with few bubbles.

Abstract: The present invention provides a glass-melting furnace etc. which can maintain homogeneity of molten glass in an apparatus and a process for producing molten glass by melting glass raw material particles and glass cullet pieces. In the present invention, glass raw material particles are dropped from a glass raw material particle heating unit 14 constituted by oxygen combustion burners 34, 34 . . . and a glass raw material particle feed portion, and the glass raw material particles are changed into liquid glass particles 38, 38 . . . in high-temperature gas phases produced by flames 32, 32 . . . of oxygen combustion burners 34, 34 . . . . In the step of heating and melting the glass raw material particles, glass cullet pieces 30, 30 . . . are feed by an feed means 40 of a glass cullet piece feed portion 12 so as to be spread radially toward the plurality of flames 32, 32 . . . around the feed portion.

Abstract: A backup structure for a pipe for feeding a molten substance of high temperature has a pipe and a thermal insulation material surrounding the pipe wherein the pipe is provided with a plurality of projections on its outer periphery at predetermined intervals, and each of the productions is held at its both sides by the thermal insulation material.

Abstract: A refining method for molten glass comprising a stirring step for stirring molten glass in a stirring vessel, a feeding step for feeding the molten glass into a vacuum vessel via an uprising pipe, a degassing step wherein the molten glass is put under a reduced pressure in the vacuum vessel, bubbles produced on the molten glass surface and a flow of the molten glass just below the molten glass surface are blocked by a barrier provided in the vacuum vessel, and the molten glass is degassed in a state that a bubble layer is formed on the molten glass surface, and a discharging step for discharging the molten glass after degassing from the vacuum vessel through a downfalling pipe to a storage vessel.

Abstract: A method for producing a glass-ceramic article, which comprises crystallizing a glass article consisting essentially of from 40 to 60% by weight of SiO.sub.2, from 13 to 19% by weight of Al.sub.2 O.sub.3, from 0 to 6% by weight of B.sub.2 O.sub.3, from 8 to 16% by weight of MgO, from 2 to 6% by weight of CaO, from 3 to 9% by weight of ZnO, from 5 to 12% by weight of TiO.sub.2, from 0 to 3% by weight of Li.sub.2 O+Na.sub.2 O+K.sub.2 O, from 0 to 3% by weight of P.sub.2 O.sub.5 and from 0 to 2% by weight of ZrO.sub.2.