Abstract: There is now provided a method and a device for the control and setting of the redox state of redox fining agents in a glass melt, in which method, during the melting process, essentially oxygen gas is blown through the glass melt.

Abstract: A system for melting and delivering glass to a work area such as spinners for making fiberglass includes a melter with heaters so arranged that the “hot spot” in the molten glass is located away from the walls and corrosion sensitive parts so that the various elements of the melter wear out at substantially the same time. The system is further provided with a dual exhaust arrangement when the melter, conditioner and forehearth are located on the same floor of the plant, the first exhaust being at the juncture of the melter and conditioner, and the second being an alternating replacement for one of the heating/cooling orifices and mechanisms in the conditioner, so as to effectively limit the amount of corrosive volatiles reaching the forehearth.

Abstract: In many engineering production processes, for example glass or glass-ceramic manufacturing processes, liquids, such as glass melts, participate in the processes in which gases are dissolved, which in part form bubbles in the liquid. So that the quality of the final product is not disadvantageously influenced, the liquid, e.g. glass melt, should be refined to remove the bubbles. According to the method of the invention an overpressure acting on the liquid is provided which is such that the internal pressure in the bubbles immediately under the surface of the liquid in a refining chamber is at least as great as the sum of equilibrium pressures of the gases dissolved in the liquid and the sum of the vapor pressure of components evaporating from the liquid. A two stage apparatus is provided which performs a preferred embodiment of the refining method of the invention.

Abstract: A method and apparatus for refining a glass melting with a vacuum generated above a surface of a glass flux. Refinement is improved because the glass flux is conducted sequentially through several vacuum chambers, and the pressure in the successive vacuum chambers is reduced more and more relative the atmospheric pressure.

Abstract: This apparatus is a furnace for heating molten material which employs oxygen-fuel burner assemblies. Preferably, the assemblies are submerged in the molten material. They are water cooled top down units with burner nozzles being off-set from the supply column. The apparatus utilizes one or more burners for each top down supply column. The supply column and attached burners can be rotated or moved in a manner to avoid the open chimney effect seen with fixed air-fuel burners of the prior art. These burners with an off-set nozzle like the letter L are rotated at high speed or oscillated to distribute the combustion in the form of gas bubbles or a gas curtain. In another embodiment, the oxy-fuel burners are not submerged. The nozzles are aimed at unmelted batch or the upper surface of the molten material for controlled splashing.

Abstract: A vacuum refining unit wherein, with a vacuum pump connected via a suction line, a vacuum is created above a glass melt to be refined. A valve for supplying secondary air from the atmosphere, for maintaining the pressure conditions in the vacuum unit constant, branches off the suction line. Refining is improved because the vacuum circuit has a controllable leak which provides an inflow of secondary air as a function of different measuring values and thus provides constant refining conditions.

Abstract: A process for producing a high-quality glass from highly reactive raw materials and a glass-melting apparatus for use therewith, comprising the step of charging a material for the glass to a molten glass in a heated vessel, (1) wherein an oxidizing gas is bubbled in the molten glass and a glass raw material that behaves as a reducing agent during being melted is charged into a position of the bubbling or (2) said vessel is filled with a dry ambient gas and while the ambient gas is allowed to flow to a liquid surface of the molten glass along an charging route of the glass raw material, the glass raw material is charged.

Abstract: A system for melting and delivering glass to a work area such as spinners for making fiberglass includes a melter with heaters so arranged that the “hot spot” in the molten glass is located away from the walls and corrosion sensitive parts so that the various elements of the melter wear out at substantially the same time. The system is further provided with a dual exhaust arrangement when the melter, conditioner and forehearth are located on the same floor of the plant, the first exhaust being at the juncture of the melter and conditioner, and the second being an alternating replacement for one of the heating/cooling orifices and mechanisms in the conditioner, so as to effectively limit the amount of corrosive volatiles reaching the forehearth.

Abstract: A system for melting and delivering glass to a work area such as spinners for making fiberglass includes a melter with heaters so arranged that the “hot spot” in the molten glass is located away from the walls and corrosion sensitive parts so that the various elements of the melter wear out at substantially the same time. The system is further provided with a dual exhaust arrangement when the melter, conditioner and forehearth are located on the same floor of the plant, the first exhaust being at the juncture of the melter and conditioner, and the second being an alternating replacement for one of the heating/cooling orifices and mechanisms in the conditioner, so as to effectively limit the amount of corrosive volatiles reaching the forehearth.

Abstract: A vacuum degassing apparatus includes a lifter to absorb deformation in a vertical direction due to thermal expansion of the vacuum degassing, a slider to absorb thermal expansion of the vacuum degassing vessel in a longitudinal direction thereof, or a thermal expansion absorbing layer to absorb thermal expansion of an uprising pipe and a downfalling pipe in a cross-sectional direction, or a thermal expansion absorbing layer provided along a portion of an outer surface of the vacuum degassing vessel in a height direction.

Abstract: A system for melting and delivering glass to a work area such as spinners for making fiberglass includes a melter with heaters so arranged that the “hot spot” in the molten glass is located away from the walls and corrosion sensitive parts so that the various elements of the melter wear out at substantially the same time. The system is further provided with a dual exhaust arrangement when the melter, conditioner and forehearth are located on the same floor of the plant, the first exhaust being at the juncture of the melter and conditioner, and the second being an alternating replacement for one of the heating/cooling orifices and mechanisms in the conditioner, so as to effectively limit the amount of corrosive volatiles reaching the forehearth.

Abstract: Molten glass has a liquid level located at a higher level than lower ends of an uprising pipe and a downfalling. In addition, a contacting portion of the uprising pipe or the downfalling pipe and a brick receiver on an upstream or downstream pit for supporting the uprising or downfalling pipe, or a joint in the brick receiver is filled with sealing material.

Abstract: A glassmelting apparatus which reduces alkali corrosion comprising: a glassmelting furnace having a plurality of walls, a crown, a charge end, a batch melting area and a fining area; at least two low momentum oxy-fuel burners located in at least one of the walls of the glassmelting furnace, each burner having at least one gas exit port, the lowest point of each gas exit port of each burner having a vertical position that is raised to a height of about 18 inches to about 36 inches above the surface of the glass; each oxy-fuel burner generating a flame along a path directed towards an opposite vertical wall of the glassmelting furnace; and said interior intersection of said walls and said crown of said glassmelting furnace being located at a height of between about 5.5 feet and 9 feet above the glassmelt surface.

Abstract: An oxy-gaseous fuel burner for a forehearth system having an oxygen conduit, a fuel conduit disposed concentrically within the oxygen conduit and forming an annulus between the fuel conduit and the oxygen conduit, a precombustor conduit disposed at the oxygen outlet end of the oxygen conduit, and a fuel tip disposed at the fuel outlet end of the fuel conduit. The outlet of the fuel tip is disposed at or upstream of the inlet to the precombustor conduit.

Abstract: An electric open-top melter for use in the manufacture of mineral fibers, such as fiberglass, is provided with a side-discharge outlet. The side-discharge outlet allows the melter, conditioner/refiner, and forehearth to all be located on substantially the same level, thereby allowing molten glass to flow from the side of the melter, through the conditioning zone, and into the forehearth from which spinners produce glass fibers or the like. Isolation members are provided in the conditioning or refining area so as to enable molten glass therein to be isolated from the melter and forehearth when the molten glass level is lowered below the tops the isolation members.

Abstract: In a glass melting furnace, a radiation screen wall is installed between a melting area and a refining area with a refining bank. This radiation screen wall leaves a flow path above the melt surface of the glass bath for the return flow of at least part of the combustion gases from the refining area to the melting area. In order to suppress a return flow of already refined and very hot glass melt from the refining area into a melting area, but still allow the charging material to melt completely as early as possible, the furnace is operated to produce at least one upward current between the middle of the melting area and the front face of the refining bank in the glass melt.

Abstract: A forehearth (20) for cooling glass from a melting furnace as it flows to a feeder bowl (28) from which it is discharged to a forming machine. The forehearth is in the form of an elongate, horizontally extending insulated trough (26) with a roof formed by a longitudinally extending series of roof block elements (30), each of which is of one-piece construction and extends completely across the width of the insulated trough. The downwardly facing surface of each roof block element is contoured to incorporate concave portions (30a, 30b) near the edges of the forehearth, a concave portion (30c) above the center of the forehearth and convex portions (30d, 30e) separating the center concave portion from the side concave portions to substantially impede heat transfer between the side concave portions and the center concave portion.

Abstract: In the manufacturing of high melting point glasses with volatile components, in particular of glasses from the group of boron glasses and borosilicate glasses, a furnace is provided that has a superstructure, fossil fuel burners, and a melting tank. In front of a conditioning zone and a throat leading to an extraction zone, a step-shaped raised area in the bottom is provided which is formed continuously over the complete width of the melting tank. In order to suppress segregation or, respectively, phase separation, to protect the furnace construction materials and to enable problem-free operation, a temperature of at least 1600.degree. C.

Abstract: In a process for manufacturing glass in a furnace a glass charge in solid form is introduced into a furnace-charging zone at an upstream part of a furnace. The glass charge is moved from the furnace-charging zone to a zone for removing the combustion smoke from the furnace downstream from the furnace-charging zone. The glass charge is moved from the zone for removing combustion smoke to a charge-melting zone downstream from the furnace-charging zone and located substantially in a middle of the furnace and heated by at least one burner. The glass charge is moved from the charge-melting zone to a charge-refining zone downstream from the charge-melting zone. The glass charge is brought to a desired temperature and viscosity in the charge-refining zone. The glass charge is removed from the furnace after the glass charge has been brought to the desired temperature and viscosity. The glass charge, after it has been removed from the furnace, is moved into a feed channel of glass-forming machines.

Abstract: A combustion assembly adapted for a furnace is provided. The assembly includes an axis comprising at least one pair of burners having axes. An oxidant lance is arranged between the burners of the pair and has a lance axis. A source of oxidant is connected to the burners and to the lance. The combustion assembly can provide uniform heating of a charge of glass in a furnace.

Abstract: An electric open-top melter for use in the manufacture of mineral fibers, such as fiberglass, is provided with a side-discharge outlet. The side-discharge outlet allows the melter, conditioner/refiner, and forehearth to all be located on substantially the same level, thereby allowing molten glass to flow from the side of the melter, through the conditioning zone, and into the forehearth from which spinners produce glass fibers or the like. Isolation members are provided in the conditioning or refining area so as to enable molten glass therein to be isolated from the melter and forehearth when the molten glass level is lowered below the tops the isolation members.

Abstract: A forehearth (20) for cooling glass from a melting furnace as it flows to a feeder bowl (28) from which it is discharged to a forming machine. The forehearth is in the form of an elongate, horizontally extending insulated trough (26) with a roof formed by a longitudinally extending series of roof block elements (30), each of which is of one-piece construction and extends completely across the width of the insulated trough. The downwardly facing surface of each roof block element is contoured to incorporate concave portions (30a, 30b) near the edges of the forehearth, a concave portion (30c) above the center of the forehearth and convex portions (30d, 30e) separating the center concave portion from the side concave portions to substantially impede heat transfer between the side concave portions and the center concave portion.

Abstract: A multi-screen mixing apparatus for installation in a fiber-forming bushing used in the manufacture of glass fibers. The multi-screen mixer attaches to the walls of the bushing, and includes a first screen having openings therein through which the glass flows and a second screen having openings through which the glass flows longitudinally spaced from the openings in the first screen such that the molten glass must flow in a non-linear path as it passes through the screens. Additional screens can be added to cause additional flow diversion to further mix the molten glass.

Abstract: A molten glass recirculating apparatus is provided, comprising a riser chamber having a first opening positioned below a molten glass level and a second opening positioned above a molten glass level, a trough positioned adjacent the upper opening, and a gas emitter positioned within the riser chamber below a molten glass level and methods of using the same. When a gas is emitted from the gas emitter, molten glass contained within the riser chamber rises and exits the riser chamber through the second opening and along the trough. The exiting molten glass causes additional molten glass to be drawn into the riser chamber through the first opening. The invention also comprises a glass melter including a plurality of glass recirculating means, each being individually controllable to control the circulation of molten glass within a glass melter.

Abstract: Method of heating the charge of a glass furnace in which at least one burner is placed in a wall of a furnace so as to heat the bath of glass, characterized in that at least one assembly consisting of a first and a second burner which are fed with fuel gas and with oxidizer gas containing at least 50 vol. % of oxygen is arranged in one of the walls of the furnace at a distance (D) at least equal to approximately 3 meters from each other, in that an oxygen lance is arranged between the first and second burners, the first burner, the second burner and the lance forming a combustion assembly and in that from approximately 30 vol. % to approximately 80 vol. % of oxidizer gas is sent into the lance and from approximately 20 vol. % to approximately 70 vol.

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 and apparatus for making float glass, wherein the glass is stirred in the conditioning zone adjacent the entrance to the float canal so as to attenuate the glass across the entire width of the float canal.

Abstract: An oxygen-gas fuel burner (12) for use in a refractory burner block (20) of glass distribution and conditioning channels (14) for thermally treating glass (18). The oxygen-gas fuel burner (12) includes a gas fuel conduit (26) extending to a central fuel outlet (28); an oxygen conduit (30) including a plurality of passages (30a) circumferentially spaced about the fuel conduit (26) and converging radially to oxygen outlets (32) circumferentially spaced about and concentric with the central fuel outlet (28); and a burner housing (34) including an outer nozzle (38). The outer nozzle (38) surrounds the fuel outlet (28) and the oxygen outlets (32) to provide a burner tip chamber (40) for mixing and combustion of oxygen and gas fuel to produce a flame within the burner tip chamber and extending outward from the burner tip chamber.

Abstract: The present invention provides an apparatus and method for reducing the occurrences of solid defects in float glass due to corrosion of refractory in a glass melting and refining furnace. In making flat glass by the float process, batch materials are fed into a melting and refining furnace and heated to form molten glass. The molten glass passes through the melting section and into a refining section of the furnace where the glass is gradually cooled and conditioned prior to delivering the glass to a forming chamber where the molten glass is floated upon molten metal and formed into a continuous sheet of glass. During the melting operation, alkali vapors from the molten glass accumulate within a downstream portion of the melting section. These vapors attack and corrode those portions of the melting section of the furnace which are constructed from silica refractory. The products of the corrosion are deposited in the molten glass resulting in solid defects.

Abstract: A process for melting glass in a horseshoe-flame furnace including a rear, a forward and a lateral wall and a longitudinal axis comprising the steps of: introducing a charge into a region of the rear wall of the furnace; running the charge, in succession in a longitudinal direction, through a melting zone to completely melt the charge and form a glass bath, through a homogenization zone and then through a refining zone; evacuating the melted and refined glass into a region of the forward wall of the furnace; sending an air-fuel flame from a first region in the rear wall which is staggered with respect to the longitudinal axis of the furnace, evacuating smoke from a second region of that same rear wall essentially symmetrically to the first region with respect to the axis; periodically alternating the first and second regions; and sending at least one oxidized fuel flame above the refining zone from a point on the lateral wail adjacent to the second region which is situated opposite the refining zone.

Abstract: A furnace (1) for melting vitrifiable materials, including a compartment (2) for melting and refining the glass equipped, upstream, with at least one means (4) for charging vitrifiable-materials and leading, downstream, into a compartment or a series or compartments (6-7-8) intended to lead the molten glass as far as the forming zone. It is equipped with a first means for controlling the convective flows of the mass of molten glass in the form of a transverse sill (14) delimiting an "upstream" zone (3) and a "downstream" zone (5). Associated with this sill are complementary means for controlling the convective flows in the "upstream" zone including, as a minimum, submerged "upstream" heating means (15) located close to and upstream of the sill, in order to prevent molten glass that has reached said the "downstream" zone from returning into the said "upstream" zone.Another subject of the invention is the application of such a furnace and the method of operating it.

Abstract: An apparatus for defibrating optically dense glass melts, such as a glass melt from basalt by the jet process, is proposed which is equipped with a feeding mechanism (1) for the melt and defibrating aggregates (2), the feeding mechanism (1) having a feed channel (3) and a subsequent distributing channel (4) with outlet ports (5) to the defibrating aggregates (2). To homogenize the glass temperature in the area before the defibrating aggregates (2) the feed channel (3) has on the bottom side at least in the area adjacent the distributing channel (4) a warming device (8) serving as a thermal barrier or active insulation and advantageously formed as an electric resistance heating device.

Abstract: A forehearth (20) for cooling glass from a melting furnace as it flows to a feeder bowl (28) from which it is discharged to a forming machine. The forehearth is in the form of an elongate, horizontally extending insulated trough (26) with a roof formed by a longitudinally extending series of roof block elements (30), each of which is of one-piece construction and extends completely across the width of the insulated trough. The downwardly facing surface of each roof block element is contoured to incorporate concave portions (30a, 30b) near the edges of the forehearth, a concave portion (30c) above the center of the forehearth and convex portions (30d, 30e) separating the center concave portion from the side concave portions to substantially impede heat transfer between the side concave portions and the center concave portion.

Abstract: An oxygen-fuel firing system for a furnace comprising separate, spread apart nozzles for introducing gaseous streams of oxygen and fuel into the furnace at spaced apart locations. The gaseous streams merge within the furnace away from the furnace walls and crown. Thus, the main combustion within the furnace takes place in the central portion of the furnace where a broad flame cloud is created. The broad flame cloud provides a more uniform temperature profile within the furnace for a more efficient processing of materials being melted in the furnace.

Abstract: At least one cooling zone and a subsequent homogenization zone are installed between the inlet and the outlet of a forehearth for conditioning and homogenizing a stream of colored glass. The glass temperature in the forehearth is reduced from the inlet temperature T1 to an outlet temperature T2. In order to increase the cooling effect while simultaneously homogenizing the glass temperature at a throughput of at least 70 tons per day, a raised area is installed in the bottom along the length of the cooling zones to set a maximum bath depth Dmax of 120 mm. Furthermore, the cooling capacity is such that the temperature 20 mm above the bottom is reduced by at least 40.degree. C. in the cooling zone. In the apparatus used, the raised area above the bottom covers the complete length of the cooling zones K. The maximum depth Dmax of the glass bath is 120 mm above the raised area and in the homogenization zone the channel is at least 30 mm deeper.

Abstract: A continuously flowing glass stream is conditioned and homogenized along a conditioning stretch, which extends from an entry side to at least one extraction point, and at the beginning of which there is a cooling zone, to which at least one homogenizing zone for the glass temperature is connected. In the working end or the distribution channel the temperature is reduced from the entry temperature T1 to an outlet temperature T2. In order to achieve the necessary conditioning and homogenization, even at high throughputs, the glass stream in the at least one cooling zone of the working end or distribution channel has a cross section with a depth/width ratio D/W of a maximum 0.6, or 0.5, or 0.4, or 0.3 or 0.

Abstract: The device for melting glass includes a compartment 1 for melting with a discharge throat 11 defined on top by a mobile carrier 16 having an upper part 18 extending upward above the level of glass and a lower part 17 intended to be totally immersed in the molten glass. Faces of the lower part are formed of a metal or an alloy of metals resistant to corrosion by the molten glass.

Abstract: A channel (1) for the outflow/conditioning of molten glass includes a duct and superstructure (5) and is designed to transfer the molten glass from a vitrifiable material melting and refining zone (6) to a molten glass forming zone, in order to take it from its melting temperature to its forming temperature. It consists of a multiplicity of successive zones (8, 9, 10, 11, 12, 13, 14) located substantially transversely in relation to its longitudinal axis, each zone having its own function, being heat-controlled in an autonomous manner and insulated over part of its height relative to the adjacent zones by partitions (15). The zones include at least one transition zone (8), at least one drainage zone (9), at least cooling zone (10, 11, 12) and at least one thermal and/or chemical homogenization zone (13, 14).

Abstract: A continuously flowing glass stream is conditioned and homogenized along a conditioning stretch, which extends from an entry side to at least one extraction point, and at the beginning of which there is a cooling zone, to which a homogenizing zone for the glass temperature is connected. This method is preferentially used for the manufacture of molded glass articles, such as containers and pressed articles. In order to achieve the necessary conditioning and homogenization, even at high throughputs, the glass stream in the cooling zone has a cross section with a depth/width ratio D/W of a maximum 0.6 or 0.5, or 0.4, or 0.3, or 0.

Abstract: An apparatus is presented for economically making crystallized glass products from waste ash produced from the sewage sludge dewatered by organic matters, which is usually regarded to be difficult to process. The melting is performed in two furnaces: the primary melting furnace and the secondary melting furnace. The primary furnace melts waste ash and the primary melt is charged into the secondary melting furnace. The glassy material produced in the secondary melting furnace is charged into a crystallization furnace to convert the glassy material to a crystallized glass product. This basic configuration of the apparatus allows the production of either irregular shaped crystallized products, such as crushed stone like products, or crystallized manufactured products, such as tiles and blocks, depending on the combination of processing equipment and their operating conditions.

Abstract: In a furnace for melting glass, a preheating zone, a melting zone, a refining zone with a refining bank raised above the rest of the floor and an homogenizing zone, are arranged lengthwise behind one another between the charging end for the glass raw materials and a throat for the molten glass. The furnace chamber formed between two end walls is split up by dividing walls with the exception of flow paths for the glass and waste gases. The melting zone, the refining zone, several burners and the homogenizing zone have a common combustion chamber in the superstructure. A first flow path "L1" for the glass is defined between the inside face of the first end wall and the vertical center line (E) of the final dividing wall in front of the refining zone, and a second flow path "L2" is defined in the combustion chamber between the vertical center line (E) and the inside face of the second end wall. The ratio of the length "L2" to the total length ("L1"+"L2") is chosen to be at least 0.5, preferably at least 0.53.

Abstract: An oxy-fuel burner for a forehearth system comprising an oxygen conduit and a fuel conduit disposed concentrically within the oxygen conduit, forming an annulus between the fuel conduit and the oxygen conduit. The fuel firing end of the fuel conduit is recessed within the oxygen conduit at a distance from the oxygen firing end of the oxygen conduit. The ratio of the inside diameter of the oxygen firing end of the oxygen conduit to the inside diameter of the fuel firing end of the fuel conduit is in the range of about 2:1 to 8:1.

Abstract: A flow duct or throat 1 for the passage of molten glass from the glass production zone to the shaping zone incorporates glass homogenizing stirrers 15, 16, 17 and 18, as well as a flow channel 2 and a heel 40. The stirrers, flow channel and heel are effective for avoiding the formation of a glass back flow.

Abstract: A glass forehearth is disclosed which is made up of upstream and downstream zones each having a roof structure which divides the channel into opposed side channels separated by a central channel. The glass in the central channel is heated for at least a portion of its length enabling the flow rate of the forehearth to be decreased.

Abstract: A glass melting tank has a melting chamber, a shallow uniflow conditioning chamber, a shallow refining chamber and a riser chamber between the melting chamber and refining chamber. Heat is input to glass in the riser chamber by electrodes located centrally in the riser chamber near the base of the riser chamber. Temperature sensors sense the temperature entering the riser chamber through a throat and near the base of a downstream wall of the riser chamber and the heat input is controlled to produce torroidal flow in the riser chamber.

Abstract: A method of controlling the exit glass temperature and the thermal homogeneity of the glass exiting from a glass forehearth having at least two temperature control zones and having in each temperature control zone at least one temperature regulating means responsive to the difference between a set point signal and an actual value signal for each temperature control zone. The temperature control method includes adjusting the set point signal of each temperature control zone as a function of the temperature of the glass entering the glass forehearth and as a function of the temperature of the glass exiting the glass forehearth.

Abstract: An oxygen-fuel firing system for a furnace comprising separate, spread apart nozzles for introducing gaseous streams of oxygen and fuel into the furnace at spaced apart locations. The gaseous streams merge within the furnace away from the furnace walls and crown. Thus, the main combustion within the furnace takes place in the central portion of the furnace where a broad flame cloud is created. The broad flame cloud provides a more uniform temperature profile within the furnace for a more efficient processing of materials being melted in the furnace.

Abstract: A forehearth for a glass furnace comprises a trough and roof over the trough, the roof having two longitudinal ridges extending downwardly towards the surface of the glass to define three longitudinal chambers. The central chamber forms a conduit for the flow of cooling air over the central part of the stream of glass and the side chambers serve as conduits for the flow of combustion gas. Separate outlets are provided for the cooling and combustion gases and controllable dampers are provided at least on the combustion gas outlets. Balancing of the internal pressures between the three chambers can ensure that there is little or no significant mixing of the cooling air and combustion gases and accurate control of the cooling and/or heating can be obtained by control of the dampers.

Abstract: The present invention provides a molten glass conveying apparatus comprising a channel (4) along which molten glass may flow, a roof structure (6) over the channel (4) and extending between the two sides thereof and at least one nozzle (28) in the roof structure (6) through which a heating fluid may be passed, wherein in use the direction of the output of the heating fluid from the nozzle (28) is substantially along the channel (4) whereby at least one side portion of the molten glass is heated.

Abstract: A forehearth for the conveyance and temperature maintenance of molten glass includes a longitudinal cooling zone over a laterally-extending cooling tile panel which is spaced above and spans an elongated trough supporting the molten glass. Roof structure of the forehearth has a pair of spaced-apart projections jutting downwardly and defining a central cooling area over the molten glass, and the central cooling area is flanked by longitudinally-extending firing chambers. Linear parallel grooves, recessed within at least one broad surface of the cooling tile panel, increase the rate of heat transfer to a longitudinally-extending air flow cavity above the cooling tile panel. The cavity has spaced air inlets along its sides that communicate with the parallel grooves of the panel and direct pressurized cooling air in laterally converging paths through the grooves and thence outwardly through a centrally located exhaust opening.