Apparatus and method for forming a glass article

Patent metadata

Field	Value
Publication number	US-11565960-B2
Application number	US-201716347395-A
Country	US
Kind code	B2
Filing date	Nov 8, 2017
Priority date	Nov 8, 2016
Publication date	Jan 31, 2023
Grant date	Jan 31, 2023

Abstract

An electrically boosted refractory melting vessel including a back wall, a first side wall, a second side wall, a front wall and a bottom wall, the melting vessel comprising a longitudinal center line extending from the back wall to the front wall and an overall width orthogonal to the longitudinal center line extending between an inside surface of the first side wall and an inside surface of the second side wall. The melting vessel also includes a length L between the back wall and the front wall, and a width W between the first side wall and the second side wall orthogonal to the center line. A plurality of electrodes extend into an interior of the melting vessel through a bottom wall of the melting vessel, and L/W is in a range from about 2.0 to about 2.4.

First claim

What is claimed is:

1. A method for producing a glass article, comprising:
feeding with at least one screw feeder a raw material into a melting vessel containing molten glass, the melting vessel comprising a back wall, a front wall, a first side wall, a second side wall and a bottom wall, the second side wall is parallel to the first side wall, the back wall is parallel to the front wall, and the bottom wall contacts the back wall, the front wall, the first side wall, and the second side wall, the back wall comprising at least one feed port opening through which the raw material is delivered into the melting vessel, the melting vessel comprising a length L extending from an inside surface of the back wall to an inside surface of the front wall, a width W orthogonal to the length L, the width W extending from an inside surface of the first side wall to an inside surface of the second side wall, a longitudinal centerline extending along the length L and equidistant from both the first and second side walls, L/W is in a range from about 2.0 to about 2.4, and L·W is equal to or less than about 17 square meters;
heating the molten glass with an electric current between a plurality of electrodes comprising molybdenum, the plurality of electrodes extending upward into an interior of the melting vessel through the bottom wall, thereby producing a plurality of convection flows in the molten glass comprising a first convection flow at a first flow velocity parallel to the longitudinal centerline in a direction toward the back wall and down the back wall toward the bottom wall, a second convection flow at a second flow velocity parallel to the longitudinal centerline toward the front wall and down the front wall toward the bottom wall, a third convection flow at a third flow velocity in a transverse direction from the longitudinal centerline toward the first side wall and down the first side wall toward the bottom wall, and a fourth convection flow at a fourth flow velocity in a transverse direction from the longitudinal centerline toward the second side wall and down the second side wall toward the bottom wall, and an inverse of an absolute value of a ratio of the third flow velocity or the fourth flow velocity to the second flow velocity at a position that is 0.05 L from the front wall and a depth that is 5.1 cm below a surface of the molten glass at a transverse position of the at least one screw feeder is greater than 50%.

2. The method according to claim 1 , L/W is in a range from about 2.2 to about 2.4.

3. The method according to claim 1 , L·W is equal to or less than about 14 square meters.

4. The method according to claim 1 , further comprising simultaneously with the heating the molten glass with the electric current, heating the molten glass with combustion burners.

5. The method according to claim 4 , an energy input to the molten glass by the electric current is from about 20% to about 80% of a total energy input into the molten glass by the electric current and the combustion burners.

6. The method according to claim 5 , the combustion burners extending through an upper portion of one or more of the first side wall or the second side wall such that flames from the combustion burner extend over the molten glass.

7. The method according to claim 1 , the melting vessel further comprising a top wall extending over the molten glass, the top wall spaced apart from the bottom wall, and wherein an integrated longitudinal flow velocity ratio of the first flow velocity to the second flow velocity along the longitudinal centerline at the depth that is 5.1 cm below a surface of the molten glass is equal to or greater than 1.5.

8. The method according to claim 1 , further comprising forming the molten glass into a glass ribbon by flowing the molten glass over converging forming surfaces.

9. The method according to claim 1 , an axis that is parallel to a direction of gravitational force intersects the bottom wall and is spaced apart from the front wall, the back wall, the first side wall, and the second side wall.

10. The method according to claim 1 , the L/W is in a range from about 2.1 to about 2.4.

11. The method according to claim 1 , the at least one screw feeder comprising a screw positioned within a conduit that extends along an axis from a storage bin to the melting vessel, the conduit attached to and in contact with the back wall of the melting vessel such that the axis extends through the at least one feed port opening.

12. A method for producing a glass article, comprising:
feeding with at least one screw feeder a raw material into a melting vessel containing molten glass, the melting vessel comprising a back wall, a front wall, a first side wall, a second side wall and a bottom wall, the second side wall is parallel to the first side wall, the back wall is parallel to the front wall, and the bottom wall contacts the back wall, the front wall, the first side wall, and the second side wall, the back wall comprising at least one feed port opening through which the raw material is delivered into the melting vessel, the melting vessel comprising a length L extending from an inside surface of the back wall to an inside surface of the front wall, a width W orthogonal to the length L, the width W extending from an inside surface of the first side wall to an inside surface of the second side wall, a longitudinal centerline extending along the length L and equidistant from both the first and second side walls, L·W is less than about 17 square meters and L/W is in a range from about 2.0 to about 2.4;
heating the molten glass by applying an electric voltage to a plurality of molybdenum-containing electrodes and establishing an electric current between the plurality of molybdenum-containing electrodes extending upward into an interior of the melting vessel through the bottom wall, such that a variation in voltage-to-ground at each electrode of the plurality of electrodes is within a range from about −80 volts to about +80 volts, thereby producing a plurality of convection flows in the molten glass comprising a first convection flow at a first flow velocity parallel to the longitudinal centerline in a direction toward the back wall and down the back wall toward the bottom wall, a second convection flow at a second flow velocity parallel to the longitudinal centerline toward the front wall and down the front wall toward the bottom wall, a third convection flow at a third flow velocity in a transverse direction from the longitudinal centerline toward the first side wall and down the first side wall toward the bottom wall, and a fourth convection flow at a fourth flow velocity in a transverse direction from the longitudinal centerline toward the second side wall and down the second side wall toward the bottom wall, and wherein an integrated longitudinal flow velocity ratio of the first flow velocity to the second flow velocity along the longitudinal centerline at a depth that is 5.1 cm below a surface of the molten glass is equal to or greater than 1.5.

13. The method according to claim 12 , further comprising simultaneously with the heating the molten glass with the electric current, heating the molten glass with combustion burners.

14. The method according to claim 13 , an energy input to the molten glass by the electric current is at least 20% of a total energy input into the molten glass by the electric current and the combustion burners.

15. The method according to claim 12 , an inverse of an absolute value of a ratio of the third flow velocity or the fourth flow velocity to the second flow velocity at a position that is 0.05 L from the front wall a

Assignees

• Corning Inc

Inventors

• Cook Mark Alan
• Gaeta Zagorka Dacic
• Lee Sung Hwan
• Nolet Daniel Arthur
• Peters Guido

Classifications

• C03B5/04

  in tank furnaces {(C03B5/02 takes precedence)} · CPC title

• C03B5/185 Primary

  Electric means · CPC title

• C03B3/005 Primary

  using screw feeders · CPC title

• Y02P40/57

  Improving the yield, e-g- reduction of reject rates · CPC title

• Y02P40/50

  Glass production, e.g. reusing waste heat during processing or shaping · CPC title