Abstract: Sheet glass is heated during conveyance within a furnace housing having a fixed roof and vertically movable side doors that define side slots through which ends of conveyor rolls project outwardly to be supported and frictionally driven by continuous drive loops slidably driven over external support surfaces that extend alongside the side slots. A vacuum holder of the apparatus is positioned within the furnace housing above the conveyor and has a downwardly facing surface with spaced openings in which a vacuum is drawn to receive a glass sheet from the conveyor and support the sheet above the conveyor. The holder surface is disclosed as being both planar and curved and as having a porous cover of ceramic fibers so as to distribute the vacuum and prevent marring of the glass as it is supported. A greater vacuum is drawn to initially support the glass and a lesser vacuum is subsequently drawn to prevent glass deformation at the spaced openings.

Abstract: A technique for finishing a diamond ground outer surface (14) of a hot glass sheet conveyor roll (16) made of sinter bonded fused silica particles utilizes a continuous abrasive belt (26) to perform a finish grinding process on the outer surface. The process is performed by rotating the roll (16) about a central axis A thereof and driving the continuous abrasive belt (26) so as to finish grind the roll while moving the driven belt along the roll length. Silicon carbide is preferably utilized as the abrasive of the belt (26). The belt is preferably driven so as to engage the rotating roll surface (14) in an oppositely moving relationship and is moved in both directions along the length of the roll. During the finish grinding, the roll is flooded with water to provide a lubricant that dissipates heat and removes ground off particles. The ground outer surface (14) includes projections (55) having top surfaces (56), sloped sides (58), and curved junctions (60) connecting the top surfaces and the sloped sides.

Abstract: Sheet glass is heated during conveyance within a furnace housing having a fixed roof and vertically movable side doors that define side slots through which ends of conveyor rolls project outwardly to be supported and frictionally driven by continuous drive loops slidably driven over external support surfaces that extend alongside the side slots. A vacuum holder of the apparatus is positioned within the furnace housing above the conveyor and has a downwardly facing surface with spaced openings in which a vacuum is drawn to receive a glass sheet from the conveyor and support the sheet above the conveyor. The holder surface is disclosed as being both planar and curved and as having a porous cover of ceramic fibers so as to distribute the vacuum and prevent marring of the glass as it is supported. A greater vacuum is drawn to initially support the glass and a lesser vacuum is subsequently drawn to prevent glass deformation at the spaced openings.

Abstract: A quench roll (20) for a glass sheet tempering system of the roller conveyor type includes a helical support (44) with a construction that does not mark conveyed glass sheets but which is nevertheless capable of withstanding breaking of glass sheets without being cut so as to require repair. The helical support (44) is wrapped about a shaft (42) of the roll (20) and includes a core (46) as well as a nonmetallic outer covering (50). The outer covering (50) is preferably a synthetic organic polymer such as silicone rubber or Teflon and, for best results, the covering has an outer sleeve (50a) of ceramic fibers. The core (46) is preferably metallic and made of wire strands (52) that facilitate wrapping thereof in the helical configuration. Spring end connections (54) disclosed prevent unwinding of the helical support (44) during glass sheet conveyance.

Abstract: Sheet glass is heated during conveyance within a furnace housing having a fixed roof and vertically movable side doors that define side slots through which ends of conveyor rolls project outwardly to be supported and frictionally driven by continuous drive loops slidably driven over external support surfaces that extend alongside the side slots. A vacuum holder of the apparatus is positioned within the furnace housing above the conveyor and has a downwardly facing surface with spaced openings in which a vacuum is drawn to receive a glass sheet from the conveyor and support the sheet above the conveyor. The holder surface is disclosed as being both planar and curved and as having a porous cover of ceramic fibers so as to distribute the vacuum and prevent marring of the glass as it is supported. A greater vacuum is drawn to initially support the glass and a lesser vacuum is subsequently drawn to prevent glass deformation at the spaced openings.

Abstract: An improved method and apparatus (12) for deep bending glass sheets disclosed provides minimal sliding of the glass sheet with respect to a curved bending mold (44) utilized, insures accurate positioning of the glass sheet on the mold for bending to the desired shape, and permits relatively abrupt end bends to be performed. A heated glass sheet (G) is initially supported against a downwardly facing surface (26) of a holder (24) above the curved bending mold (44) which has an upwardly concave shape. An upward gas flow (49) from a gas supply unit (48) at a central portion (50) of the glass sheet (G) is supplied and continued as opposite extremities (52) of the glass sheet are released and dropped downwardly onto the mold. Thereafter, termination of the upward gas flow (49) from the gas supply unit (48) releases the central portion (50) of the glass sheet (G) for bending on the mold (44). After the bending, a mold is moved to a quench unit (22) for tempering of the bent glass sheet.

Abstract: Sheet glass is heated during conveyance on a conveyor within a furnace. A vacuum holder is positioned within the furnace housing above the conveyor and has a downwardly facing surface with spaced openings in which a vacuum is drawn to receive a glass sheet from the conveyor and support the sheet above the conveyor. The holder surface is disclosed as being both planar and curved and as having a porous cover of ceramic fibers so as to distribute the vacuum and prevent marring of the glass as it is supported. Auxiliary lifters positioned between the rolls or vertical movement of the vacuum holder facilitates glass pickup. A carrier mold ring moves under the supported glass and the vacuum is then terminated so the glass drops onto the ring and bends under the bias of gravity in a manner that allows thin glass to be accurately bent. Subsequently the mold ring is moved from the furnace to a quench unit that temper the bent glass.

Abstract: A method and apparatus for filming and tempering a pre-cut glass sheet in a continuous process. The glass sheet is heated initially to a temperature sufficient for pyrolysis. The heated glass is sprayed with a coating composition which reacts with the glass to form a metal oxide film on its surface. The filmed glass is re-heated to both restore the heat lost by spraying and to bring its temperature to a level sufficient for tempering. The glass sheet is then tempered by subjecting it to rapid cooling. The method can be modified to include a secondary spraying wherein after the glass is first sprayed it is re-heated as in the initial step and then re-sprayed before completing the process. Apparatus for carrying out the above described method is also disclosed.

Abstract: A gas jet pump (10) for producing a secondary flow of gas from a primary flow. The jet pump is disclosed as a tubular body (28) having a flow passage into which the primary flow is introduced through a plurality of jet openings (36, 38, 40) in the tubular body. Each jet opening has axial and circumferential components and is tangent with the surface defining the flow passage so as to produce a vortical flow in an axial direction within the body upon introduction of high pressure gas through the openings. The primary flow produces an amplified secondary flow through the tubular body. An annular manifold (22, 24, 26) is mounted on the tubular body to selectively feed the primary flow to the jet openings. The gas jet pump has application in sheet glass treating apparatus (50, 110), and has particular utility in apparatus used to bend sheet glass. A method of manufacturing a gas jet pump is also disclosed.

Abstract: Apparatus and a method disclosed for use in bending heated sheets of glass (G) transported generally horizontally on a conveyor (16) within a furnace heating chamber incorporate a holder (20) located above the conveyor in a spaced relationship such that a heated sheet of glass can be transported under the holder. Gas such as air is blown upwardly from below the conveyor against the heated sheet of glass such that the sheet is moved upwardly into engagement with the holder. The upwardly blown gas is provided by an array of gas jet pumps (60) positioned below the conveyor. A mold ring (44) is then movable under the holder to receive the glass sheet for bending. Holder (20) is disclosed as including curved and planar surfaces and as including curved and planar rings. A vacuum may be drawn with the holder embodiments having the surfaces so as to assist the upwardly blown gas in lifting the sheet of glass off the conveyor.

Abstract: A system (10) and method disclosed for use in bending glass incorporate a vacuum holder (12) having a surface (28) with spaced openings (32) in which a vacuum is drawn to support a heated sheet of glass (G) and in which pressurized gas is subsequently supplied to force the glass sheet away from the holder surface. In one embodiment, operation of a control damper (24) initially communicates a vacuum blower (20) with the holder and subsequently communicates a positive pressure air blower (22) therewith to first draw the vacuum and then supply the pressurized air to the openings in the surface which is disclosed facing downwardly. During an intermediate step, the damper is positioned so that a reduced vacuum is drawn to prevent deformation of the heated glass sheet at the spaced openings in the holder surface. In an alternative embodiment, a gas jet pump (90) is used to produce the positive and vacuum pressures used in the practice of the invention.

Abstract: A high temperature furnace particularly adapted for fusing crystalline silica includes a housing defining a heating chamber that receives electrically conductive elements with insulators positioned therebetween to establish an electrical flow path for heating the chamber. Resilient gas cylinders located externally of the housing bias graphite connecting rods that extend into the heating chamber to compress and position the conductive elements and the insulators therebetween while allowing expansion thereof during heating of the chamber. Graphite wall panels preferably define the housing heating chamber and have interlocking edges that position the panels relative to each other. Cooperable pairs of resilient gas cylinders at longitudinal ends of the furnace housing compress the wall panels to maintain the edges thereof in their interlocking relationship while permitting expansion during heating of the chamber.

Abstract: The glass tempering system includes an elongated furnace in which a horizontal conveyor oscillates a glass sheet between opposite ends of the chamber in a manner to shorten the necessary furnace length to heat the glass to its quench temperature. A load station at one end includes a horizontal conveyor driven by the same drive mechanism as the furnace conveyor during the index cycle so that a glass sheet is received while another glass sheet is being indexed to the quench unit. A second motor drives the quench unit conveyor in an oscillating manner. The two drive mechanisms are coupled during the index cycle so that a tempered glass sheet is conveyed from the quench unit to an unload station as a heated glass sheet is being conveyed to the quench unit. The conveyor of the unload station is driven by the quench unit drive during the index cycle to receive the tempered glass sheet. Each of the conveyors includes drive chains which frictionally drive their conveyor rollers.

Abstract: A furnace for treating glass sheet material and the like in a glass tempering system. The furnace includes an upper glass treating zone and a lower gas treating and distributing zone for homogenizing gases of different temperatures to minimize exposure of the sheet being treated in the treating zone to uneven temperatures. Diametrically opposed inlets and outlets are provided in the side walls controlled by doors, and a slot in the top wall extends between the inlets and outlets to permit movement of a material carrier through the furnace. A pressure chamber communicates with the slot to cool conveyor elements at the top of the furnace, and also to provide a pressure barrier resisting the escape of gases from the furnace through the slots. Air curtains impinge on the tops of the doors in their closed positions to reduce leakage at the top of the doors.

Abstract: A roller hearth furnace having a plurality of horizontally elongated furnace modules aligned with each other in an end-to-end relationship so a roller conveyor may carry glass sheets horizontally through the furnace and thereby heat the glass prior to tempering. Each furnace module has a hollow construction with a circular cross-section defined by a semicircular lower housing portion and a semicircular upper housing portion. A separate counterbalance mechanism associated with each upper housing portion supports it independently of the others for movement between a lower closed position immediately over its associated lower housing portion and an upper open position where the interior of its associated lower housing portion is accessible. The counterbalance mechanisms each include four chains attached to counterweights in a manner that permits counter-balancing of the associated upper housing portion even if one chain should break.

Abstract: A glass tempering blasthead including a pair of plenum chambers with opposed banks of nozzles for directing air or other fluid flow onto opposite surfaces of a sheet of glass disposed therebetween for quenching or cooling the glass subsequent to heat treatment of the glass. Each plenum chamber has a fluid flow distributing assembly including a pair of complementary sheet members. Each of the sheet members is stamped so that when secured in complementary relationship with the other sheet member a series of nozzles are formed having flared inlets communicating with a transverse feed passage for directing flow from the plenum chamber into the flared inlets of the nozzles. When the glass sheets are disposed horizontally between the opposed nozzles, the nozzles have their axes disposed parallel to the vertical.

Abstract: A glass tempering system including a roller hearth furnace that has a conveyor with elongated rollers extending through an elongated heating chamber of the furnace and outwardly through elongated slots in the sides of the furnace so as to be supported on drive belts which are slidably driven along support surfaces to thereby frictionally drive the rollers and convey glass sheets over the rollers through the heating chamber. The furnace is of a modular construction and includes upper and lower housing portions with inner layers of refractory material that define the heating chamber. Flanges of the refractory material cooperate to define the elongated slots at the sides of the furnace. Heat seal arrangements extend between the refractory flanges and the conveyor rollers to mitigate heat flow from the furnace during use. A first electric motor drive mechanism drives belt sheaves that receive the drive belt at the end of the furnace where glass enters the heating chamber.

Abstract: A furnace for heat treating glass sheet material including a circular enclosure having top, bottom and side walls of refractory material. Inlet and outlet openings are formed in the side walls. The side walls have an outer insulating layer and an inner layer of material having a low coefficient of thermal expansion, the inner layer having spaced end portions projecting beyond the outer layers and the periphery of the side walls to define said inlet and outlet openings. Each opening is controlled by doors, and each door includes an elongated support bar with a plurality of blocks of refractory material supported on the bar in end-to-end relationship. The blocks are adjustably secured to the bar to accommodate irregularities in the openings.