Abstract: The invention envisions a method for improving the thermal shock resistance of glass objects. For this a glass object is heated starting from a surface temperature under the softening point (42) on the surface of a first side (3) until the viscosity reaches or goes below a value of 10(7.65±2) poise.

Abstract: Disclosed is an apparatus and method for heat treating glass sheets, and in particular for heat treating very thing glass sheets arranged in closely spaced stacks. The glass sheets are positioned on a moving belt such that their major surfaces are substantially perpendicular to a direction of belt travel through the apparatus to aid in producing a uniform temperature profile within the glass sheets. The apparatus comprises air curtains positioned at the inlet and outlet of the apparatus to minimize the ingress of particulate into the apparatus. A reduced velocity of heated air flow within a lower portion of the apparatus relative to a velocity of the heated air in an upper portion of the apparatus causes particulate to drop out of the lower portion air flow. A rotating brush and vacuums positioned adjacent a lower portion of the belt assist in removing particulate from the moving belt.

Abstract: A method for manufacturing glass hard disk substrates comprises annealing and then tempering previously formed glass hard disk substrates. The annealed and tempered glass hard disk substrates have improved strength and stress resistance without chemical treatments.

Abstract: A convection heating furnace for a glass sheet, into which oven glass sheet (3) arrives along a hauling track, as on moving rolls (4), and said furnace further comprises of heating elements (12), in order to heat the air, which is blasted against glass sheet (3), a blaster and blast air channelling in order to blast said air against the glass sheet, and the blast air channelling has, elongated channels (1), into which at least a part of the blast air heating elements 12 are fitted, and each channel comprises air blasting means on its flank directed against the glass sheet (3). As air blast elements there are nozzle groups fixed on the channel (1) flank, where the nozzle group formed of sheet metal, as of two, into shape formed sheets joined together to form a casing, whereby said casing comprises one or several for blast air directed discharge channels (6), and the direction of air flow in said casing (2) is essentially in the same direction as in said discharge channels (6).

Abstract: Glass is heated from above and below while the glass resides on rolls (3) in a tempering furnace (1). The upper surface of the glass (4) is heated by hot air jets formed by sucking air from inside the furnace (1) and pressurizing the hot air and recycling it back to the upper surface of the glass. Air which has been taken from outside the furnace (1) and pressurized by a compressor (17) and heated is blown to the lower surface of the glass.

Abstract: A process for producing a synthetic silica glass optical component which contains at least 1×1017 molecules/cm3 and has an OH concentration of at most 200 ppm and substantially no reduction type defects, by treating a synthetic silica glass having a hydrogen molecule content of less than 1×1017 molecules/cm3 at a temperature of from 300 to 600° C. in a hydrogen gas-containing atmosphere at a pressure of from 2 to 30 atms.

Abstract: Method for transferring heat onto a glass in the furnace meant for heat treatment of glass, into which glass is transferred on a path of rollers, furnace heated by resistors (5) located inside of the furnace, the radiation heat directed onto the glass and convection heat transferred by means of a blower and air onto the glass. In the method the glass being heated and roller space (8) are separated by a wall (9) from air circulation space (3, 7), by means of blowers the air circulation is arranged to heat above and/or below the glass by means of the first chamber (7) and second chamber (3), wherein air is sucked by the blower from the first chamber and blowed into the second chamber, wherein air circulation is conducted from the vicinity of the glass and from roller space (8) through an opening in the wall (9) into vertical channels (7C2) and further into the first chamber and chamber the glass is directed onto the glass through nozzles (6).

Abstract: A method and apparatus for heating glass sheets in preparation of tempering. A furnace (1) is provided with upper and lower convection blasting conduits (11, 14) extending lengthwise of the furnace. The furnace is also provided with upper and lower radiation heating elements (12, 16). The convection heating air is pressurized with a compressor (3), cleaned with a filter (4). The upper convection heating air is heated with air discharged from the furnace in a plurality of separate heat exchangers (7), through which the convection heating air is passed into the upper convection blasting conduits (11). The amount of air discharged from the furnace (1) through the heat exchangers (7) is substantially equal to that blasted into the furnace for convection heating.

Abstract: In a firing furnace of plasma display panel, gas distribution piping and gas exhaust piping each have a circular cross section and a uniform diameter along the longitudinal direction of those pipings. The gas distribution piping has a plurality of circular openings formed in a side face thereof and the openings are constructed such that the opening becomes larger in a stepwise fashion in a direction from both end portions to the central portion of the gas distribution piping. Furthermore, the gas exhaust piping has a plurality of elliptic openings formed in a side face thereof and the openings are constructed such that the opening becomes larger in a stepwise fashion in a direction from both end portions to the central portion of the gas exhaust piping.

Abstract: A semi-convective forced air system for heating glass sheets during a heating cycle comprises a heating chamber having a length and a width, at least one heating element located within the heating chamber, a conveyor having a length and a width, the conveyor extending lengthwise through the heating chamber, a compressed air source, a plurality of air manifolds positioned within the heating chamber and in fluid connection with the compressed air source, each of the air manifolds having a length, and each of the air manifolds being oriented parallel to the length of the conveyor, and a plurality of nozzles mounted on each air manifold and in fluid connection with the air manifold for mixing together and directing toward the conveyor a combination of compressed air and over air to convectively heat a sheet of glass on the conveyor, the plurality of nozzles on each air manifold being spaced along the length of the air manifold.

Abstract: In a method and an apparatus for heating glass panels in a tempering furnace equipped with rollers, glass panels are carried on a conveyor defined by rollers into a tempering furnace for the duration of a heating cycle, followed by carrying the glass panels into a tempering station. The glass panels are heated in the tempering furnace by bottom- and top-heating radiation elements as well as by bottom- and top-heating convection elements through which convection air is supplied to the tempering furnace. The glass panels' bottom side is heated by the bottom-heating convection elements, which are arranged lengthwise along the furnace and define convection heating zones side by side in a lateral direction of the tempering furnace. Thus, convection heating effects of the convection heating zones can be altered relative to each other for profiling the heat transfer coefficient in a lateral direction of the furnace.

Abstract: A method and apparatus for heating glass, in which glass (4) is heated upon rollers (3) in a tempering furnace (1) from above and below of the glass (4). At least the upper surface of the glass (4) is heated with hot air jets directed substantially perpendicularly relative to the surface of the glass (4). The air jets have been provided by sucking air mainly from the inside of the furnace and by pressurizing the air taken from the inside of the tempering furnace (1) to an overpressure of over 0.1 bar relative to the pressure in the tempering furnace (1).

Abstract: A method and apparatus for heating glass, in which glass (4) is heated upon rollers (3) in a tempering furnace (1) from above and below of the glass (4). At least the upper surface of the glass (4) is heated with hot air jets directed substantially perpendicularly relative to the surface of the glass (4). The air jets have been provided by sucking air mainly from the inside of the furnace and by pressurizing the air taken from the inside of the tempering furnace (1) to an overpressure of over 0.1 bar relative to the pressure in the tempering furnace (1).

Abstract: Method for transferring heat onto a glass in the furnace meant for heat treatment of glass, into which glass is transferred on a path of rollers, furnace heated by resistors (5) located inside of the furnace, the radiation heat directed onto the glass and convection heat transferred by means of a blower and air onto the glass. In the method the glass being heated and roller space (8) are separated by a wall (9) from air circulation space (3, 7), by means of blowers the air circulation is arranged to heat the glass above and/or below the glass by means of the first chamber (7) and second chamber (3), wherein air is sucked by the blower from the first chamber and blowed into the second chamber, wherein air circulation is conducted from the vicinity of the glass and from roller space (8) through an opening in the wall (9) into vertical channels (7C2) and further into the first chamber and from second chamber the glass is directed onto the glass through nozzles (6).

Abstract: The invention concerns a method and a device for heating glass sheets in an oven, which are transported therein by a conveyor with horizontal rollers and wherein their surfaces are heated by heating means arranged above and beneath the sheets, by radiation and by forced convection by injecting hot gas into the oven, the gas injected beneath being in the form of jets whereof the axis of symmetry is oblique relative to the forward moving direction of the sheets on the conveyor and directed towards their lower surface.

Abstract: A furnace (10) and method for heating conveyed glass sheets within a housing (12) includes forced convection heaters (24) spaced along the direction of conveyance both below and above a roll conveyor (20). Each forced convection heater (24) includes a gas burner assembly (32) generally adjacent one of the housing side walls and has an outlet (34) through which products of combustion are supplied to the housing heating chamber (18) at a location intermediate its side walls. A hot gas distributor (38) of each forced convection heater (24) includes an inlet (40) that is spaced from the outlet (34) of the gas burner assembly (32), and the hot gas distributor (38) has a suction fan (42) for drawing in heated products of combustion together with spent recirculating gas in the heating chamber (18) for mixing to provide heated gas that is distributed to the conveyed glass sheets.

Abstract: A furnace (10) and method for heating conveyed glass sheets within a housing (12) includes forced convection heaters (24) spaced along the direction of conveyance both below and above a roll conveyor (20). Each forced convection heater (24) includes a gas burner assembly (32) generally adjacent one of the housing side walls and has an outlet (34) through which products of combustion are supplied to the housing heating chamber (18) at a location intermediate its side walls. A hot gas distributor (38) of each forced convection heater (24) includes an inlet (40) that is spaced from the outlet (34) of the gas burner assembly (32), and the hot gas distributor (38) has a suction fan (42) for drawing in heated products of combustion together with spent recirculating gas in the heating chamber (18) for mixing to provide heated gas that is distributed to the conveyed glass sheets.

Abstract: A method and apparatus for heating glass sheets in preparation of tempering. A furnace (1) is provided with upper and lower convection blasting conduits (11, 14) extending lengthwise of the furnace. The furnace is also provided with upper and lower radiation heating elements (12, 16). The convection heating air is pressurized with a compressor (3), cleaned with a filter (4). The upper convection heating air is heated with air discharged from the furnace in a plurality of separate heat exchangers (7), through which the convection heating air is passed into the upper convection blasting conduits (11). The amount of air discharged from the furnace (1) through the heat exchangers (7) is substantially equal to that blasted into the furnace for convection heating.

Abstract: A glass sheet quench station (16) includes first and second quench sections (24 and 26) that cooperate with a three position shuttle (28) and a control (30) to transfer glass sheets through the quench station with partial quenching performed at the first quench station and completion of the quenching at the second quench section. This glass sheet quenching method with two stage quenching shortens the cycle time to provide increased production.

Abstract: A semi-convective forced air system for heating glass sheets during a heating cycle comprises a heating chamber having a length and a width, at least one heating element located within the heating chamber, a conveyor having a length and a width, the conveyor extending lengthwise through the heating chamber, a compressed air source, a plurality of air manifolds positioned within the heating chamber and in fluid connection with the compressed air source, each of the air manifolds having a length, and each of the air manifolds being oriented parallel to the length of the conveyor, and a plurality of nozzles mounted on each air manifold and in fluid connection with the air manifold for mixing together and directing toward the conveyor a combination of compressed air and over air to convectively heat a sheet of glass on the conveyor, the plurality of nozzles on each air manifold being spaced along the length of the air manifold.

Abstract: A method of heating low emissivity glass sheet for subsequent processing. The glass sheet is loaded onto a longitudinally extending conveyor and oriented such that the lengthwise edge of the sheet is parallel to the length of the conveyor and the direction of conveyance of the glass sheet. The sheet is conveyed into a heating chamber. The glass sheet is then convectively heated in a specified sequence along the entire length of the glass sheet at selected areas measured along the width by creating a downward flow of heated air proximate the selected areas.

Abstract: The invention relates to a method for heating glass sheets to be tempered or heat-strengthened, in which method glass sheets are heated in a preheating furnace (1) by applying a hot-air blast and convection heating produced thereby to the opposite sides of a glass sheet and the preheated glass sheet is transferred from the preheating furnace (1) into a radiation heating furnace (2) for heating the glass sheet to a tempering temperature. During the convection heating of a glass sheet, the rotating speed of a hot-air fan (5) is increased while adjusting the heating effect of heating resistances (6) so as to maintain the temperature of blasted air substantially constant. Thus, the diminishing temperature difference between glass and air is compensated for by controlling the coefficient of heat transfer.

Abstract: A method for heating LowE glass panels in a tempering furnace (1) provided with rollers. LowE glass panels are carried on a conveyor constituted by rollers (2) into the tempering furnace and then the discussed glass panels are set in an oscillating motion within the tempering furnace for the duration of a heating cycle. This is followed by delivering the discussed glass panels into a tempering station (3). In the tempering furnace, the glass panels are heated by means of top and bottom radiation heating elements (4, 5), as well as by top and bottom convection heating elements (6, 7). In the early stage of a heating cycle the top glass surface is subjected to convection heating more powerful than that applied to the bottom surface and in the final stage of a heating cycle the bottom glass surface is subjected to convection heating more powerful than that applied to the top surface.

Abstract: A roller furnace for heating windows to their softening temperature. The furnace is provided above a roller transportation track. Vanes forming blowing nozzles are arranged transversely to the direction of movement of the windows in order to blow hot gas onto the top surface of the window. A radiative heater is provided below the roller transportation track to heat the bottom of the window.

Abstract: A method for making a furnace for heating a glass sheet by lower electric resistance elements (50) supported by a furnace housing (12) below a roll conveyor (40) and by supplying a gas burner heated hot gas flow from a forced convection heater (56) that provides a dominant mode of external heat for heating the conveyed glass sheet from above. The furnace is manufactured by retrofitting an electric resistance heater type glass sheet furnace that initially has both lower and upper electric resistance elements (50) located below and above the roller conveyor (40). The lower electric resistance elements (50) are maintained while the upper electric resistance elements (50) are replaced with a gas burner forced convection heater (56).

Abstract: A forced convection furnace (20) and method for heating glass sheets includes a forced convection heater (42) having lower hot gas distributors (44) located below alternate conveyor rolls (38) to provide upward gas flow both upstream and downstream thereof along a direction of conveyance to provide heating from below of the glass sheets being conveyed within a heating chamber (32) of a housing (22) of the furnace. The forced convection heater (42) also includes upper hot gas distributors (52) for providing heating from above of the glass sheets being conveyed within the heating chamber (32).

Abstract: A method and furnace for heating a glass sheet by lower electric resistance elements (50) supported by a furnace housing (12) below a roll conveyor (40) and by supplying a gas burner heated hot gas flow from a forced convection heater (56) that provides a dominant mode of external heat for heating the conveyed glass sheet from above. The furnace can also be manufactured by retrofitting an electric resistance heater type glass sheet furnace.

Abstract: The invention relates to a process for the heat-soak treatment of tempered glass panels. After tempering, the glass is heated or cooling of the glass is stopped for maintaining the temperature for the duration of e.g. a good minute within the range of 340-370.degree. C., such that the glasses, which break spontaneously in time as a result of NiS-stones, can be broken already in a so-called heat-soak treatment. During the heating sequence or the cooling stop sequence and during the subsequent cooling sequence, the glass panel is carried in a horizontal plane, e.g. back and forth on rollers in an oscillating fashion. The process is a continuous-action process and the apparatus for implementing the same can be hooked up with a tempering machine for an on-line operation.

Abstract: A forced convection furnace (20) and method for heating glass sheets includes a forced convection heater (42) having lower hot gas distributors (44) located below alternate conveyor rolls (38) to provide upward gas flow both upstream and downstream thereof along a direction of conveyance to provide heating from below of the glass sheets being conveyed within a heating chamber (32) of a housing (22) of the furnace. The forced convection heater (42) also includes upper hot gas distributors (52) for providing heating from above of the glass sheets being conveyed within the heating chamber (32).

Abstract: A semi-convective forced air system for heating glass sheets during a heating cycle. The system has a heating chamber, and a longitudinal conveyor extending lengthwise through the heating chamber. A plurality of longitidinally-extending air manifolds are located within the chamber and are in fluid connection with a compressed air source. The manifolds are arranged in at least one widthwise-extending column. Each of the manifolds are oriented parallel to the length of the conveyor and are constructed and arranged to create a downward flow of heated air toward the conveyor to convectively heat the entire length of selected widthwise portions of a sheet of glass on the conveyor. A controller supplies or restricts the flow of compressed air to selected manifolds within a column at predetermined times during the heating cycle.

Abstract: A glass sheet strip annealing method utilizes a housing (18) along which a conveyor (26) including a gas support (28) supports a glass sheet strip G by pressurized gas for movement between entry and exit ends (22,24) of the housing before a conveyor drive (32) engages the strip after the surfaces thereof are cooled below the strain point. Best results are achieved when the glass sheet strip is supported only by the gas support (28) until its surfaces are placed in compression. Lower and upper manifolds (34,36) respectively support and convey the glass sheet strip within the housing (18) preferably by a recirculating gas flow supplied by gas burner (76) and associated gas jet pumps (78).

Abstract: A process for quenching a heated glass sheet is performed by apparatus (26) that includes a pair of quench units (28) between which the glass sheet is located with each quench unit having nozzles (34) for directing cryogenic flows (36) including a liquid (42) toward the oppositely facing surfaces (38) of the glass sheet so that the liquid completely vaporizes before penetrating the gas boundary layer (40) on each surface of the glass sheet. The cryogenic flows (36) can be initially completely liquid (42) or can be a two phase as the liquid (42) and a gas (44) with the latter preferably being done by spraying the two phase cryogenic flows as liquid droplets and the gas.

Abstract: A process for quenching heated glass sheets is performed by locating a glass sheet between a pair of spaced quench units (28) and directing from first and second arrays of nozzles (34, 64) cryogenic flows (36) interspersed with pressurized air flows (66) so as to cooperate with each other in providing the quenching. In one practice the interspersed cryogenic flows (36) and the pressurized air flows (66) are provided at the same time as each other. In another practice, the interspersed cryogenic flows (36) and pressurized air flows (66) are provided at different times.

Abstract: A method and an apparatus for coating a hot glass substrate with a mist of fine droplets from a solution of a chemical precursor or mixture of precursors in a solvent, by nebulizing a solution with ultrasonic vibration to form a mist of fine droplets; conducting the mist to the hot glass substrate; and depositing the mist on the hot glass substrate to pirolize it and form the desired coating on the glass substrate. The nebulization is carried out by applying vibration of ultrasonic frequency to the solution obtaining the mist of fine droplets and conducting the fine droplets by a stream of a carrier gas, to be deposited on a surface of the hot glass substrate, particularly on a continuous glass ribbon during production in the float glass manufacturing process mainly at the beginning of the annealing chamber where the temperature of glass ribbon is 580.degree. C.-610.degree. C.

Abstract: A method of tempering an article is disclosed in which an article is heated so that the material making up the article is in an essentially stress-free state and the article thereafter is quenched and cooled. At the conclusion of the quenching, a stress pattern in initiated through the thickness of the article in which the midplane layer is in tension and the surface layers are in compression. This stress pattern is further developed during the cooling stage. The article is quenched by spraying the surfaces with a coolant, preferably comprising either liquid nitrogen or liquid air in the form of a two phase flow of liquid and vapor. The liquid is sprayed so that the surface tensile stress of the surface layers are not exceeded and the liquid does not accumulate on the surface layers as a film.

Abstract: A forced convection heating apparatus and process for heating glass sheets therewithin. The apparatus includes at least one gas burner for producing hot combustion gases to be distributed toward and into contact with the top and/or bottom surfaces of a glass sheet within the apparatus housing. The temperature of the hot combustion gases which is distributed to the top surface of the glass sheet is adjustable independently of the temperature of the hot combustion gases being distributed to the bottom surface of the glass sheet to, in turn, enable independent control of convection heat transfer to both surfaces of the glass sheet.

Abstract: A forced convection heating apparatus and process for heating glass sheets therewithin. The apparatus includes at least one gas burner for producing hot combustion gases which is to be distributed to the top and/or bottom surfaces of a glass sheet within the apparatus housing. Spent hot working fluid, which has impinged the top and bottom surfaces of the glass sheet, is drawn into a mixing chamber operably positioned about a gas burner. The spent hot working fluid and newly produced hot combustion gases from the gas burner are mixed within the mixing chamber and then distributed toward and into operable contact with at least one of the top and bottom surfaces of the glass sheet.

Abstract: A forced convection heating apparatus and process for heating glass sheets therewithin. The apparatus includes at least one gas burner for producing hot combustion gases which is to be distributed toward and into contact with the top and/or bottom surfaces of a glass sheet within the apparatus housing. The velocity of the distributed hot combustion gases which eventually impinges upon the top surface of the glass sheet is controllable independently of the impingement velocity of the hot combustion gases being distributed, and, in turn, directed toward and into contact with the bottom surface of the glass sheet.

Abstract: A method and apparatus for annealing glass sheets, in which glass sheets are retained within a frame having edge retaining members. The edge retaining members retain the edges of the glass sheet during the annealing operation, thereby hindering warpage and surface damage of the glass sheet during the annealing process.

Abstract: A glass sheet strip annealing lehr (16) is disclosed as including a housing (18) along which a conveyor (26) including a gas support (28) supports a glass sheet strip G by pressurized gas for movement between entry and exit ends (22,24) of the housing before a conveyor drive (32) engages the strip after the surfaces thereof are cooled below the strain point. Best results are achieved when the glass sheet strip is supported only by the gas support (28) until its surfaces are placed in compression. Lower and upper manifolds (34,36) respectively support and convey the glass sheet strip within the housing (18) preferably by a recirculating gas flow supplied by gas burner (76) and associated gas jet pumps (78).

Abstract: The invention relates to an assembly in the annealing section of a glass tempering apparatus, comprising a glass sheet supporting rollers and cooling air blow boxes disposed above and below a glass sheet. A blast pressure applied to the bottom surface of a glass sheet may tend to pick up a glass sheet and float the sheet off contact with the rollers. In order to correct the situation without changing the cooling effects on the opposite surfaces of glass, the radiation absorption factor of surfaces below a glass sheet is higher than the absorption factor of surfaces above on the thermal radiation wavelengths of glass. Thus, the blast pressure on a top surface of the glass sheet has been increased with respect to the blast pressure on a lower surface of the glass sheet.

Abstract: The present invention relates to a process and a device for applying tensile forces, with no contact with solid walls, to glass sheets, in particular at high temperatures, wherein a gas or vapor is blown between the glass sheet and a wall closely approached, and parallel, to said glass sheet. Between the glass sheet and said wall a gas cushion is established, in that the sections through which the gas flows inside the air gap between the glass sheet and the wall increase on the average in the direction of streaming of the gas, so as to allow the gas speed to decrease, and a recovery in gas pressure to consequently take place. Several forms of practical embodiment of the device are disclosed.

Abstract: A glass sheet tempering method and resultant glass sheet are disclosed as being provided by modulated quenching that initially cools the oppositely facing surfaces of a conveyed glass sheet at a first cooling station (14) with a first rate of heat transfer for a finite time to cool the surfaces from tempering temperature to below the strain point without cooling the center of the glass sheet below the strain point. Thereafter the oppositely facing surfaces of the conveyed glass sheet are cooled within a second cooling station (15) at a second rate of heat transfer less than the first rate to initially cool the center of the glass sheet below the strain point without corresponding surface cooling, and thereafter further cools the center and the sruface. The second rate of heat transfer is of a magnitude so that the surface temperature initially increases without going back substantially above the strain point prior to subsequently again cooling.

Abstract: A gas burner (20) disclosed has general utility but has particular utility when utilized in a closely spaced relationship to roller conveyed glass sheets to provide forced convection heating. The burner (20) includes a cobbustion member (38) in which gas and air are introduced in a tangential relationship with respect to its inner surface to provide a swirling motion that mixes the gas with the air for combustion prior to discharge through outlets (46) to provide the forced convection heating. A glass sheet heated by this gas burner forced convection on the roller conveyor and subsequently cooled has reduced roll-wave distortion and reduced edge distortion as compared to radiantly heated glass sheets.

Abstract: Improved burner constructions for gas-fired infra-red generators having ceramic fiber matrix through the thickness of which gaseous combustion mixture is passed and as it emerges it is burned to heat emerging surface to incandescene. Burner matrix can be loaded with silicon carbide particles to improve its emissivity, can be made water repellent and its uniformity can be improved. Burner body can be casting, with sheet metal addition to form a baffle and air seal and to grip matrix edges. Combustion mixture plenum can have movable partition assembly separating it from air seals, to adjust portion of matrix at which incandescene is generated. Metal screen can be stretched in front of incandescent surface to assist with low-temperature operation. Large size matrix can have central support fitted and secured to back of burner body. Air seal can be provided by narrow curtain of air extending around internal faces of burner body.

Abstract: The invention relates to a flow barrier in the annealing section of a glass tempering apparatus, said annealing section being provided with glass sheet supporting rollers (7) and cooling air blow boxes (1, 3) are disposed above and below a glass sheet, in addition to which there are, above the glass sheets, "false rolls" (8) in the form of a downward open trough, extending crosswise to the traveling direction of said glass sheets. The purpose of "false rolls" (8) is to increase a pressure applied to the top surface of a glass sheet in order to reduce the risk of a glass sheet becoming afloat. A flow along the trough, which increases towards the ends of the trough, results in a non-uniform tempering. The flow is cut off by fitting the trough with partitions (9) spaced from each other.

Abstract: An exhaust oven for cathode ray tubes having a housing and a baffle structure arranged within the housing for forming an atmosphere circulating passage between them. There are formed, at least in heating and slow cooling zones within the housing, plural pairs of upper discharge ports through which the circulating atmosphere is supplied towards panel portions of the cathode ray tubes. There are also plural pairs of lower discharge ports through which the circulating atmosphere is supplied towards funnel portions of the cathode ray tubes. Both the upper and lower discharge ports are located on respective sides in the housing. The positioning and discharge direction of the upper and lower discharge ports reduce the temperature difference between different portions of the cathode ray tubes to less than 10.degree. C. Thus, breakage of tubes owing to heat stresses is virtually eliminated.

Abstract: A furnace (12) including a roller conveyor (18) and gas burners (20) distinct from the conveyor for supplying forced convection that is the dominant mode of heat transfer to glass sheets during a heating process. The gas burners (20) have general utility but have particular utility when utilized in a closely spaced relationship to the roller conveyed glass sheet to provide the forced convection heating. Each burner (20) includes a combustion member (38) defining an elongated combustion chamber (42) extending transversely to the direction of conveyance. Gas and air are introduced into the combustion chamber (42) in a tangential relationship with respect to its inner surface to provide a swirling motion that mixes the gas with the air for combustion prior to discharge through outlets (46) to provide the forced convection heating.

Abstract: A glass sheet tempering method and system (10) disclosed utilizes a heating chamber (22) and a quenching chamber (26) which contain ambients at superatmospheric pressure during both the heating and quenching. Forced convection heating is preferably performed in an improved furnace (14"). In one embodiment, heated gas flow is provided by centrifugal blowers which blow air across a plurality of spaced heat tubes. The heated gas flow is directed toward a glass sheet positioned within the heating chamber to provide rapid heating of the glass sheet. In a second embodiment, the heated gas flow is provided by upper and lower sets of opposed gas jet pumps connected to a gas supply. A pressure gas supply including a compressor maintains the superatmospheric pressure of the heating and quenching chambers (22,26). A recirculating gas supply (32) feeds compressed quenching gas to opposed blastheads (28,30) to perform the tempering.

Abstract: A method is provided for the manufacture of glass containers (10) of the type having a sidewall (12) and having a bottom (16) that is thicker than the sidewall (12). The method comprises a step in which a centered portion (44) of the bottom (16) is cooled subsequent to the molding step. Cooling the centered portion (44) is effective to develop a reverse strain in the transition portion (42a) of the sidewall (12) that is proximal to the bottom (16). This reverse strain corrects the strain that is induced by unequal cooling of a relatively thin sidewall (12) and a relatively thick bottom (16) and results in a reduction of annealing time.