Ppg Industries, Inc.

Ppg Industries Ohio, Inc.

Other

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

George A Pecoraro

Larry J Shelestak

Charlene S Smith

Gerald E Kunkle

Joseph E Cooper

Richard Markovic

James Victor Jones

Robert B Heithoff

Yih-Wan Tsai

Henry M Demarest, Jr

Joseph A Gulotta

Gary N Hughes

Amarendra Mishra

Kwang J Won

Jerry C Ratliff

Richard L Bayne

James C Stultz

A float glass chamber and related methods include a hot section having an atmosphere in at least the lower plenum with less than 3 percent hydrogen based on volume and a cold section having a different volume percent hydrogen.

Apparatus and methods for producing float glass having reduced defect density

A method for reducing the defect density of glass comprising melting a glass composition comprising from 65-75 wt. % of SiO; from 10-20 wt. % of NaO; from 5-15 wt. % of CaO; from 0-5 wt. % of MgO; from 0-5 wt. % of AlO; from 0-5 wt. % of KO; from 0-2 wt. % FeO; and from 0-2% FeO, wherein the glass composition has a total field strength index of greater than or equal to 1.23 is disclosed.

Method for making float glass having reduced defect density

A method for reducing the defect density of glass comprising melting a glass composition comprising from 65&#x2013;75 wt. % of SiO; from 10&#x2013;20 wt. % of NaO; from 5&#x2013;15 wt. % of CaO; from 0&#x2013;5 wt. % of MgO; from 0&#x2013;5 wt. % of AlO; from 0&#x2013;5 wt. % of KO; from 0&#x2013;2 wt. % FeO; and from 0&#x2013;2 % FeO, wherein the glass composition has a total field strength index of greater than or equal to 1.23 is disclosed.

A method is provided for adjusting, e.g., lowering, the melting and/or forming temperatures of a glass composition without substantially changing the bending and annealing temperatures of the glass composition. The method includes increasing the amount of CaO and decreasing the amount of MgO in the glass composition by the same or about the same amount.

Methods of adjusting glass melting and forming temperatures without substantially changing bending and annealing temperatures and glass articles produced thereby

A method is provided for adjusting, e.g., lowering, the melting and/or forming and/or liquidus temperatures of a glass composition which can be accomplished without substantially changing the bending and annealing temperatures of the glass composition. The method includes decreasing the amount of MgO in the glass composition and increasing the amount of two or more or all of CaO, R O (Na O and K O), Al O and SiO by the same or about the same amount.

Methods of adjusting temperatures of glass characteristics and glass articles produced thereby

A glass product having high visible transmittance, low infrared transmittance, and, optionally, reduced ultraviolet transmittance is produced in a manner compatible with continuous, commercial manufacture of flat glass by employing a moderate amount of iron in the glass composition and controlling reducing conditions to maintain a relatively large portion of the iron in the ferrous state.

Transparent infrared absorbing glass and method of making

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. In the present invention, a nonreactive gas is directed into the downstream portion of the melting section at a temperature no greater than that of the molten glass within the melting section and at a gas volume sufficient to reduce the amount of alkali vapors in the downstream portion of the melting section. As a result, the corrosion of the silica refractory is reduced and the total occurrences of solid defects in the glass due to refractory corrosion is reduced. In one embodiment of the invention, the gas is the combustion products from burners that are positioned in the downstream portion of the melting section of the furnace.

Reduction of solid defects in glass due to refractory corrosion in a

Material selected from the group consisting essentially of molybdenum, arsenic, antimony, bismuth, copper, silver, potassium dichromate and iron chromite, is added during the manufacture of soda-lime-silica float glass to reduce the occurrences of nickel sulfide stone defects. Material is added in sufficient amounts such that the resulting glass is at least 0.010 wt. % selected material. In a preferred embodiment of the invention, molybdenum is added in the form of sodium molybdate such that the resulting glass is at least 0.015 wt. % molybdenum.

Reduction of nickel sulfide stones in a glass melting operation

In a method of vacuum refining molten glass or the like, sufficient concentrations of volatilizable substances are provided in the molten material. prior to entering the vacuum refiner so as to cause at least an eight-fold volume increase during foaming and thereby increase removal of gases from the molten material.

Vacuum refining of glassy materials with selected foaming rate

In a method of vacuum refining molten glass or the like, sufficient concentration of water is provided in the molten material so as to cause enhanced foaming.

Vacuum refining of glassy materials with selected water content

The potential for fused cast ceramic refractories to release stones into molten material with which it is in contact is reduced by subjecting the refractory to a vacuum pretreatment to remove gases from the glassy phase of the refractory. Preferably the treatment is carried out when the refractory is in a molten state.

Pretreatment of fused cast refractories

A multilayered, cooled metal lid for a heating vessel has a main support plate fabricated from low carbon steel and a chromium steel overlay that is exposed to the hot interior portions of the vessel. The chromium steel overlay has a chromium content by weight of approximately 10 to 25 percent.

Lid construction for a heating vessel and method of use

A glass product having high visible transmittance, low infrared transmittance, and, optionally, reduced ultraviolet transmittance is produced in a manner compatible with continuous, commercial manufacture of flat glass by employing a moderate amount of iron in the glass composition and controlling reducing conditons to maintain a relatively large portion of the iron in the ferrous state.

A lid of a glass batch melting vessel is subjected to corrosive and thermal degradation. The lid is cooled and the temperature of the exploded inner surface of the lid is controlled such that particulate and molten materials entrained in exhaust gas circulating within the vessel adhere to the lid surface forming a protective, insulating coating that prolongs the service life of the lid.

Batch melting vessel lid cooling construction

Stirring of glass of high optical quality is effected by initiating forming of the glass, such as by the float process, at relatively high temperatures immediately after the glass has been stirred. Preferably, during and/or following the stirring operation contact between the molten glass and ceramic refractories is minimized. This is preferably accomplished by providing a layer of molton metal (e.g., tin) on the bottom of the stirring chamber.

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Lower Burrell, PA, United States of America

George A Pecoraro