All-ceramic glass making system

Claim 2

In a system for making glass including a melter positioned within a furnace and heating elements for heating said melter, the improvement comprising a muffle interposed between said melter and said heating elements, said muffle surrounding and extending axially above and below said melter so that homogenization of the temperature distribution in said melter is accomplished, and said muffle being spaced from said melter so that said melter may be separately inserted and withdrawn from said furnace.

Claim 3

The system as set forth in claim 1 wherein said muffle has a cylindrical shape.

Claim 4

A stirrer for homogenizing a glass melt comprising a hollow cylindrical shaft having at least one blade formed thereon, said hollow cylindrical shaft having at least one aperture through a sidewall thereof, said at least one aperture being positioned so as to be located beneath the surface of the glass melt when said stirrer is utilized in a melter, and means for introducing a flow of gas into said hollow cylindrical shaft whereby said at least one blade and gas escaping from said hollow cylindrical shaft through said at least one aperture cooperate in homogenizing the glass melt.

Claim 5

A stirrer for homogenizing a glass melt comprising a hollow cylindrical shaft having at least one blade formed thereon, said hollow cylindrical shaft having at least one aperture through a sidewall thereof, said at least one aperture being positioned so as to be located beneath the surface of the glass melt when said stirrer is utilized in a melter, and means for introducing a flow of gas into said hollow cylindrical shaft whereby said at least one blade and gas escaping from said hollow cylindrical shaft through said at least one aperture cooperate in homogenizing the glass melt.

Claim 6

The stirrer as set forth in claim 3 wherein said stirrer is formed of an all-ceramic material.

Claim 7

The stirrer as set forth in claim 4 wherein said all-ceramic material is mullite.

Claim 8

The stirrer as set forth in claim 5 wherein said mullite has the following composition in percent by weight: Al2O3 63.0 SiO2 37.0

Claim 9

The stirrer as set forth in claim 4 wherein said all-ceramic material consists essentially of Al2O3 of a purity of at least 96 percent by weight with the balance of the composition being inert impurities.

Claim 10

The stirrer as set forth in claim 5 wherein said all-ceramic material consists essentially of the following ranges of composition in percent by weight: Al2O3 49-51 ZrO2 34-37 SiO2 11-15 with the balance of the composition being modifying oxides.

Claim 11

In a system for making glass including a furnace and a melter wherein the improvement comprises a stirrer for homogenizing glass melts, said stirrer comprising a hollow cylindrical shaft having at least one blade formed thereon, said hollow cylindrical shaft having at least one aperture through a sidewall thereof, said at least one aperture being positioned so as to be located beneath the surface of the glass melt when said stirrer is utilized in said melter, and means for introducing a flow of gas into said hollow cylindrical shaft whereby said at least one blade and gas escaping from said hollow cylindrical shaft through said at least one aperture cooperate in homogenizing the glass melt.

Claim 12

In a system for making glass including a furnace and a melter wherein the improvement comprises a stirrer for homogenizing glass melts, said stirrer comprising a hollow cylindrical shaft having at least one blade formed thereon, said hollow cylindrical shaft having at least one aperture through a sidewall thereof, said at least one aperture being positioned so as to be located beneath the surface of the glass melt when said stirrer is utilized in said melter, and means for introducing a flow of gas into said hollow cylindrical shaft whereby said at least one blade and gas escaping from said hollow cylindrical shaft through said at least one aperture cooperate in homogenizing the glass melt.

Claim 13

In a system for making glass including a furnace and a melter wherein the improvement comprises a stirrer for homogenizing glass melts, said stirrer comprising a hollow cylindrical shaft having a blade formed thereon and means for introducing a flow of gas into said shaft, wherein said stirrer has at least one aperture positioned to be located beneath the surface of molten glass when the stirrer is utilized in a melter, wherein said stirrer is formed of an all-ceramic material.

Claim 14

In a system for making glass including a furnace and a melter wherein the improvement comprises a stirrer for homogenizing glass melts, said stirrer comprising a hollow cylindrical shaft having a blade formed thereon and means for introducing a flow of gas into said shaft, wherein said stirrer has at least one aperture positioned to be located beneath the surface of molten glass when the stirrer is utilized in a melter, wherein said stirrer is formed of an all-ceramic material.

Claim 15

The stirrer as set forth in claim 10 wherein said all-ceramic material is mullite.

Claim 16

In a system for making glass including a furnace and a melter wherein the improvement comprises a stirrer for homogenizing glass melts, said stirrer comprising a hollow cylindrical shaft having a blade formed thereon and means for introducing a flow of gas into said shaft, including means for rotating said stirrer clockwise and counter-clockwise.

Claim 17

In a system for making glass including a furnace and a melter wherein the improvement comprises a stirrer for homogenizing glass melts, said stirrer comprising a hollow cylindrical shaft having a blade formed thereon and means for introducing a flow of gas into said shaft, including means for rotating said stirrer clockwise and counter-clockwise.

Claim 18

The system as set forth in claim 12 including means for oscillating said stirrer vertically.

Claim 19

The system as set forth in claim 13 including means for oscillating said stirrer horizontally.

Claim 20

The system as set forth in claim 14 including a cylindrical muffle surrounding said melter.

Claim 21

The system as set forth in claim 14 wherein said melter has a hemispherical bottom having an orifice positioned on the gravitational center of said bottom and an orifice tube integrally formed on said melter and surrounding said orifice tube.

Claim 22

The system as set forth in claim 16 wherein said hemispherical bottom is supported on a rotatable hearth.

Claim 23

The system as set forth in claim 17 including means for rotating said hearth.

Claim 24

The system as set forth in claim 18 wherein said rotatable hearth is stepped to form a stepped bottom on said furnace.

Claim 25

The system as set forth in claim 17 wherein said orifice tube extends into said hearth, said hearth having at least one heating element positioned therein for heating said orifice tube.

Claim 26

The system as set forth in claim 20 wherein said melter, said stirrer and said orifice tube are formed of an all-ceramic material.

Claim 27

The system as set forth in claim 21 wherein said all-ceramic material is mullite.

Claim 28

In a system for making glass including a furnace, a melter, a stirrer associated with the melter, and a muffle surrounding the melter, wherein the improvement comprises said melter, stirrer, and muffle being formed essentially completely from an all-ceramic material, said all-ceramic material being selected from the group consisting of mullite, alumina of a purity of at least 96 percent by weight, and a material which consists essentially of the following ranges of composition in percent by weight: Al2O3 49-51 ZrO2 34-37 SiO2 11-15.

Claim 29

In a system for making glass including a furnace, a melter, a stirrer associated with the melter, and a muffle surrounding the melter, wherein the improvement comprises said melter, stirrer, and muffle being formed essentially completely from an all-ceramic material, said all-ceramic material being selected from the group consisting of mullite, alumina of a purity of at least 96 percent by weight, and a material which consists essentially of the following ranges of composition in percent by weight: Al2O3 49-51 ZrO2 34-37 SiO2 11-15.