Ppg Industries, Inc.

Ppg Industries Ohio, Inc.

Vitro, S.a.b. De C.v.

DeWitt W Lampman

Robert G Frank

Michael T Fecik

Raymond J Mouly

George R Claassen

Gerald E Kunkle

William R Siskos

Rudolph A Karlo

Terry A Bennett

Jack A Bricker

Joseph Medzius

Irvin A Wilson

Mark M Savka

W Jason Skeen

Steven M Horcicak

Thomas M Sailock

Lawrence S Letzkus

Herbert W Eilenfeld

William R Krall, Jr

Michael Zibert

Jr William R Krall

A method of tempering a glass sheet heated to a tempering temperature includes cooling the glass sheet at a first heat transfer coefficient at a first quench station and cooling the glass sheet at a second heat transfer coefficient at a second quench station downstream of the first quench station. The second heat transfer coefficient is greater than the first heat transfer coefficient. In a multistage process of the invention, a plurality of quench stations could be used with each downstream quench station having a larger heat transfer coefficient than the previous upstream quench station.

Apparatus and method for tempering glass sheets

The present invention is directed to an apparatus for thermal treatment of glass and method and thermally treated glass therefrom. The apparatus is capable of supporting the glass during thermal treatment such as tempering, annealing, bending, and/or shaping which can include any cooling or quenching to remove heat or any combination of these. The apparatus is a support member like a ring or outline mold with a horizontal surface suitable for contacting the glass. The support member has at least a surface with or without a coating for contact with the glass of one or more metals having a thermal conductivity such that the glass heated for shaping cools at a rate not much slower than the cooling rate of unsupported sections of the glass. Suitable metals include those with a thermal conductivity of greater than around 16 BTU/(hour&times;feet&times;&deg; F.). When a coating covers at least a portion of the support, the coating can give the support member more heat resistance and/or anti-corrosiveness and/or abrasion resistance to improve durability. Also the support member can be the shaping rail of a windshield or backlite shaping iron.

Apparatus for thermal treatment of glass and method and thermally treated glass therefrom

The present invention provides a quench for cooling hot sheet material. The quench includes a plurality of generally horizontally extending, spaced apart nozzle assemblies, each having a longitudinally extending air supply conduit with orifices extending to an outer surface of the conduit. A first plenum is interconnected to a first end of each of the conduits and a second plenum is interconnected to a second end of each of the conduits to allow cooling fluid to pass from the plenums into each of the nozzle assemblies through the conduit. The plenums are located at positions spaced laterally outward from the nozzle assemblies.

Glass sheet quench

A horizontal press bending arrangement for press bending heat softened glass sheets during transfer into a shaping station. The glass sheet is conveyed through a roller hearth or gaseous support hearth type furnace to heat the sheet to its heat deformable temperature. The sheet is then transferred beneath a vacuum/pressure pick-up to support the glass sheet in non-engaging contact therewith. The sheet is next deposited on a lower mold. The vacuum/pressure pick-up thereafter splits in two and moves out of the shaping station to allow the sheet to be shaped between a pair of vertically aligned shaping molds. After shaping the shaped sheet is removed for further processing, e.g., tempering.

Horizontal press bending using a splitting vacuum/pressure pickup

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

Discrete glass sheet cutting

A sliding support table to support a continuously advancing glass ribbon during severing. The ribbon is supported by and moves over the sliding support table which moves along the direction of the glass ribbon travel between stationary upstream and downstream supports. Top and bottom line heaters supported on the table direct flames towards the major surfaces of the glass ribbon along a line cut. A blade and anvil arrangement supported on the table, sever the glass along the heated line of cut when the line of cut is positioned therebetween. The table advances along with the glass ribbon to support the ribbon during the heating and severing operation. The line heaters and blade and anvil arrangement may provide both a linear or nonlinear line of cut.

Ribbon severing support

In tempering a glass sheet to a high temper by heating the sheet to approximately its softening point followed by rapid chilling using a quenching composition that comprises a tempering medium having high heat transfer characterisitcs, the heat-softened glass sheets are protected from breakage during fabrication and resulting optical distortion by applying the tempering medium through exit orifices of a delivery system toward the heated glass in a novel cycle. The initially applied tempering medium has a low heat transfer rate and is mixed with a second tempering medium having a higher heat transfer rate to gradually increase the heat transfer rate of the mixed tempering medium. In a specific embodiment, dry air is the first tempering medium and a sublimable material, such as carbon dioxide, is the second tempering medium. The delivery system has an uninsulated portion that assures that initially the sublimable material is applied as a gas. Dry air which has a lesser heat transfer coefficient than the sublimable material in its gaseous state, may be supplied to the uninsulated portion if humidity conditions require so that dry air having a lesser heat transfer coefficient is initially directed through the exit orifices followed by mixtures of dry air with increasing concentrations of said sublimable material in the gaseous state followed by increasing concentrations of solid particles of said sublimable material. Movement of the glass sheet is coordinated with movement of the delivery system for said quenching composition to avoid 'batter'.

Tempering glass sheets by cooling comprising sublimation quenching

This invention relates to method and apparatus for handling glass sheets during shaping and cooling. Each glass sheet to be treated in turn is heated to its deformation temperature and conveyed through a furnace and into a glass shaping station by a roller conveyor. The glass is lifted into engagement with a vacuum shaping mold while hot and held against the vacuum shaping mold by vacuum as the glass lifting mechanism retracts downward. A tempering ring having an outline supporting surface conforming to and slightly inside the periphery of the bent glass sheet is brought into position below the upper vacuum mold. The vacuum on the upper mold is released to deposit the shaped glass sheet on the tempering ring. The latter supports and transfers the bent glass sheet during movement into a cooling station where the shaped glass sheet is quenched as rapidly as possible to harden the glass surface and enable a plurality of rotating rolls to lift the hardened glass sheet from the tempering ring and convey it onto additional conveyor rolls which transport the shaped glass between additional streams of cooling medium such as air blasts that impart at least a partial temper to the glass. When the glass is transferred to the additional conveyor rolls, the rotating transfer rolls are lowered to clear the path of movement for the tempering ring to return to the shaping station where the cycle is repeated.

Method and apparatus for handling glass sheets for shaping and cooling

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Gibsonia, PA, United States of America

DeWitt W Lampman