Abstract: The potential for fused cast ceramic refractories to release stones into molten material with which it is in contact is reduced by subjecting the refractory to a vacuum pretreatment to remove gases from the glassy phase of the refractory. Preferably the treatment is carried out when the refractory is in a molten state.

Abstract: A lid of a glass batch melting vessel is subjected to corrosive and thermal degradation. The lid is cooled and the temperature of the exploded inner surface of the lid is controlled such that particulate and molten materials entrained in exhaust gas circulating within the vessel adhere to the lid surface forming a protective, insulating coating that prolongs the service life of the lid.

Abstract: Glass shapes and sheets are cut directly from a heated glass ribbon while maintaining the optical quality of the cut glass. A float glass ribbon is removed from a glass forming chamber and prior to annealing, a line of cut is heated to its softening temperature. A blade arrangement thereafter penetrates the glass along the heated line of cut to sever the glass. During the line heating and cutting operation, the overall glass temperature is maintained above the strain point of the glass.

Abstract: Delivery of molten glass to a flat glass forming operation carried out as a substantially free-falling vertical stream. The glass may be received in a first chamber in a relatively deep and narrow reservoir, from which it flows to a wider chamber, from which, in turn, it is drawn longitudinally.

Abstract: Method and apparatus are provided for refining glassy material or the like by vacuum. The material is first melted and then introduced into a vacuum chamber, preferably into space above liquid held in the chamber. Other aspects involve a two-step melting process preparatory to the vacuum refining, in which the material is initially liquefied in one stage and dissolution of particles is substantially completed in a second stage. The molten material is preferably foamed immediately upon entry into the vacuum chamber.

Abstract: Converting thermally meltable materials to a liquefied state is carried out on a lining of pulverulent material. As liquefied material is drained from the surface, additional unmelted material is fed onto the surface to maintain the lining substantially intact.

Abstract: Raw materials such as glass batch are preheated by combustion of liquid or solid fuel such as fuel oil or coal mixed with the batch material. In one embodiment the material being heated and the gaseous products of combustion are passed cocurrently through the preheating stage to avoid carbonaceous effluents. Preheated materials and any ash from the fuel are transferred to a second stage where they are liquefied. Carbon monoxide from the preheating stage may serve as fuel for the liquefying stage.

Abstract: Thermally fusible material such as glass batch is liquefied using a solid carbonaceous fuel such as coal as the major energy source. In another embodiment, solid or liquid fuel is mixed with the batch material being fed to an initial liquefaction stage. Melting may be advanced further in a subsequent stage where the melt may also be re-oxidized.

Abstract: In a glass batch liquefying process, batch-entrained nitrogen is purged by contacting the batch with a substantially nitrogen-free gas in a pretreating stage.

Abstract: Converting thermally meltable materials to a liquefied state is carried out on a lining of pulverulent material. As liquefied material is drained from the surface, additional unmelted material is fed onto the surface to maintain the lining substantially intact.

Abstract: Converting thermally meltable materials to a liquefied state is carried out on a support surface of the unmelted material. As liquefied material is drained from the surface, additional unmelted material is fed onto the surface to maintain a substantially constant layer of the unmelted material.

Abstract: A continuous ribbon of glass is reduced in thickness while supported on molten metal by imposing super-atmospheric pressure over a molten glass layer in a chamber where the glass is maintained in contact with the side walls of the chamber. One aspect features metering the glass layer into the pressure chamber at substantially full width. Another aspect involves pressure sizing the glass layer at temperatures above 2100.degree. F. (1150.degree. C.).

Abstract: The initial step of melting glass, converting particulate batch materials to a partially melted, liquefied state, is carried out on a support surface of batch. As liquefied batch is drained from the surface, additional batch is fed onto the surface to maintain the surface substantially constant.

Abstract: A method and apparatus for glass delivery to a forming chamber are disclosed. The forming entrance bottom comprises an upward facing convex surface wherein the highest point of the convex surface extends generally in the direction of glass movement.

Abstract: Flat glass having superior optical quality is continuously produced by a contiguous float process in which lamellar flows are established in a molten glass conditioner and the flow patterns are maintained in a stream of glass unidirectionally delivered onto a pool of molten metal on which the glass is cooled and unidirectionally attenuated to form a ribbon of glass.

Abstract: In the manufacture of flat glass, molten glass is delivered along a substantially horizontal delivery path onto a pool of molten metal. A stream of molten glass is deeper along its marginal portions than its central portion in order to provide for substantially uniform flow rates across the entire stream of molten glass. A continuous ribbon of flat glass of any thickness may be uniformly formed in a very short distance extending downstream from the delivery as a result of delivering the glass in this manner.

Abstract: A layer of molten glass is discharged from a pool of molten glass in a glassmaking furnace and delivered along a substantially horizontal path onto a pool of molten metal in a forming chamber; the glass is then advanced along the surface of the pool of molten metal while being cooled to form a continuous sheet of glass. Prior to discharge and delivery, the molten glass is conditioned to establish an accelerated flow of molten glass in the direction of its delivery. The glass is conditioned by selectively cooling the glass at different depths in the pool of molten glass across the width of the delivery path just prior to delivery to preferentially decelerate the flow of hotter, less viscous glass at one location in the pool of molten glass relative to the flow of cooler, more viscous glass at another location in the pool. In this way the molten glass is caused to uniformly flow into a region for discharge from the pool and delivery for forming.

Abstract: Glass advancing along the surface of a pool of molten metal and being formed into a continuous sheet of flat glass is controllably cooled by advancing over successive molten metal containing compartments partially separated from one another by barriers and each provided with individually controllable cooling facilities.

Abstract: The initial step of melting glass, converting particulate batch materials to a partially melted, liquefied state, is carried out on a support surface of batch. As liquefied batch is drained from the surface, additional batch is fed onto the surface to maintain the surface substantially constant.The questions raised in reexamination request No. 90/000,701, filed Dec. 31, 1984 have been considered and the results thereof are reflected in this reissue patent which constitutes the reexamination certificate required by 35 U.S.C. 307 as provided in 37 CFR 1.570(e).