Abstract: In a regenerative furnace of the type used for melting glass, localized overheating of the regenerator packing is minimized, heating of the regenerator packing is made more uniform, and regenerator efficiency is improved by employing a gas stream, preferably a high velocity burner, in the plenum of the regenerator to control gas flow distribution within the regenerator.

Abstract: Optical quality of float glass is improved by attenuating longitudinally prior to attenuating laterally and by carrying out each attenuation step within specified temperature ranges.

Abstract: In a regenerative furnace of the type used for melting glass, localized overheating of the regenerator packing is minimized, heating of the regenerator packing is made more uniform, and regenerator efficiency is improved by employing air jets in the space alongside the regenerator packing opposite the flue to counteract flow imbalances in the regenerator.

Abstract: Afterburning is employed with selective, non-catalytic reduction by ammonia injection to reduce NO.sub.x emissions of a process furnace, especially a glass melting furnace.

Abstract: Apparatus for selectively heating marginal edge portions of a stream of molten glass includes at least two independent heating elements presenting a substantially planar heating face toward the marginal edge of a stream of molten glass flowing in close proximity thereunder. A first set of the heating elements overlies a portion of the marginal edge adjacent a containing sidewall and the second set is positioned inboard of the first set relative to the central portion of the stream. Generated heat is directed primarily downward, e.g., greater than about fifty percent, and preferably greater than seventy-five percent toward first and second distinct areas of the marginal edge by a thermal insulating barrier positioned over the heating elements, to provide first and second localized zones of heating. The heating elements may be cantilevered through the sidewall in close proximity to the stream of molten glass.

Abstract: A method of controlling the erosion of a refractory threshold over which molten glass flows transverse to the longitudinal centerline thereof, which includes preferentially cooling the central portion of the threshold while maintaining the marginal edge portions at a temperature above the liquidus temperature of the molten glass. A cooling fluid conduit extending longitudinally through the refractory threshold is thermally insulated adjacent its end portions, thereby localizing the cooling effect towards the central portion of the threshold.

Abstract: Optical quality of float glass is improved by attenuating longitudinally prior to attenuating laterally and by providing cooled marginal edge portions of the glass ribbon during lateral attenuation.

Abstract: In a glass melting operation, cullet is employed as a waste heat collector and/or particulate emissions collector. Cullet is contacted with exhaust gases in a gas/solid contact vessel wherein the cullet is heated and particulates are deposited onto the cullet. The heated cullet is preferably sent directly to the melting furnace. Electrostatic means may be employed to enhance particulate collection in the bed of cullet.

Abstract: Granular heat exchange medium is employed to recover waste heat from a combustion furnace, particularly a glass melting furnace, and the heated medium is then employed to pre-heat combustion air entering the furnace. A bed of granular heat exchange medium also may remove particulate emissions from the exhaust gas.

Abstract: A method of vertically positioning ribbon engaging devices in a glass forming chamber includes suspending a contact member within the chamber a known vertical distance relative to the device, moving the contact member toward the surface of a pool of molten metal contained within the glass forming chamber while moving the device to maintain the known vertical distance; and generating a signal when the contact member engages the pool of molten metal to indicate that the device is vertically positioned said known vertical distance from the surface of the pool of molten metal.

Abstract: A method of and apparatus for attenuating a ribbon of float glass in a temperature region below 1500.degree. F. (815.degree. C.) to diminish undesirable longitudinally oriented optical distortions. A cylindrical ribbon engaging device is rotated about an axis of rotation substantially parallel to the ribbon surface and the direction of ribbon flow to positively exert a plurality of outwardly directed lateral forces to an elongated substantial continuum of the marginal edge portion of the ribbon. Ribbon engaging elements are disposed about the circumferential surface of the cylindrical device in elongated helical paths, and the cylindrical device is rotated at an angular velocity such that the product of the angular velocity and the pitch of the helical paths equals the longitudinal velocity of the ribbon flow while the device acts upon the ribbon surface.

Abstract: A float glass forming chamber is provided with electrical heating elements having separate housings and separate electrical shut-off means, so that any heating element can be independently disconnected for replacement or for modifying the heating pattern.

Abstract: Auxiliary heat is provided to a float glass forming chamber by means of a prewired portable heating module which may be inserted or removed from an operating forming chamber. In particular, the auxiliary heating arrangement is adapted to provide temporary center heat in a forming chamber which is primarily heated along side portions.

Abstract: A float glass forming chamber is provided with a simplified roof structure having a reduced number of vertically extending joints and openings. The roof is comprised of relatively large refractory slabs suspended from above by a hanger arrangement external to the forming chamber enclosure.

Abstract: A tweel flow control device at the entrance to a flat glass forming chamber is provided with overhead support and elevator means, preferably adapted to convey the tweel from its operative location.

Abstract: In a flat glass melting and forming installation, the threshold between a melting furnace and a forming chamber is supported on movable cart means to expedite installation and removal of the threshold.

Abstract: NO.sub.x emissions from a glass melting furnace are reduced by injecting ammonia into the exhaust gas stream on a flue between primary and secondary regenerator chambers in one embodiment, and in staged zones within a regenerator in another embodiment.

Abstract: A float glass forming chamber with electrical heating means is provided with a plurality of compact housings to enclose electrical connections, thereby avoiding the conventional overhead plenum chamber. Also, a gas-tight casing directly overlying the roof elements serves to minimize the volume of the overhead structure. Both features reduce condensation and drippage of volatile materials within the chamber and improve access to forming chamber elements.

Abstract: A float glass forming chamber is provided with heating elements that extend through the side walls of the chamber. As a result, the roof of the chamber may be of simpler construction, the heating elements are more accessible, and electrical connections can be more conveniently arranged.

Abstract: A float glass forming chamber is provided with a simplified roof structure comprised of suspended refractory slabs, whereby the number of joints and non-planar interior surfaces are reduced so as to suppress condensation and drippage of volatile materials within the chamber.