Apparatus and method for mitigating electrochemical attack of precious metal components in a glass making process

Patent metadata

Field	Value
Publication number	US-12091352-B2
Application number	US-201917279950-A
Country	US
Kind code	B2
Filing date	Sep 20, 2019
Priority date	Sep 28, 2018
Publication date	Sep 17, 2024
Grant date	Sep 17, 2024

Abstract

Apparatus and methods are disclosed for forming a glass article in which molten glass is heated in a refractory vessel defining a space interior to the refractory vessel. A precious metal component is exposed to the interior space. The apparatus includes first and second electrodes exposed to the interior space. A first electrical power source configured to supply a first electrical current is connected between the first and second electrodes. A second electrical power source is connected between the precious metal component and at least one of the first electrode or a first auxiliary electrode and configured to provide a second electrical current out-of-phase with the first electrical current. A third electrical power source is connected between the precious metal component and at least one of the second electrode or a second auxiliary electrode and configured to provide a third electrical current out-of-phase with the first electrical current.

First claim

What is claimed is:

1. An apparatus for forming a glass article, comprising:
a refractory vessel defining an interior space configured to hold molten glass;
a precious metal component exposed to the interior space and arranged to contact the molten glass;
a first alternating current electrical power source electrically connected between first and second electrodes exposed to the interior space and arranged to contact the molten glass, the first alternating current electrical power source configured to supply a first electrical current;
a second alternating current electrical power source electrically connected between the precious metal component and at least one of the first electrode or a first auxiliary electrode arranged to contact the molten glass, the second electrical power source configured to supply a second electrical current out-of-phase with the first electrical current; and
a third alternating current electrical power source electrically connected between the precious metal component and at least one of the second electrode or a second auxiliary electrode arranged to contact the molten glass, the second electrical power source configured to supply a third electrical current out-of-phase with the first electrical current.

2. The apparatus according to claim 1 , wherein the first alternating current electrical power source, the first electrode, and the second electrode comprise a first electrical circuit.

3. The apparatus according to claim 2 , wherein the second alternating current electrical power source, the precious metal component, and the at least one of the first electrode or the first auxiliary electrode comprise a first electrical biasing circuit.

4. The apparatus according to claim 3 , wherein the third alternating current electrical power source, the precious metal component, and the at least one of the second electrode or the second auxiliary electrode comprise a second electrical biasing circuit.

5. The apparatus according to claim 1 , wherein the refractory vessel comprises at least one of a melting vessel, a fining vessel, or a forehearth.

6. The apparatus according to claim 1 , wherein the first and second electrodes comprise tin or molybdenum.

7. The apparatus according to claim 1 , wherein the first auxiliary electrode comprises tin or molybdenum.

8. The apparatus according to claim 1 , wherein the second auxiliary electrode comprises tin or molybdenum.

9. The apparatus according to claim 1 , wherein the second alternating current electrical power source is configured such that an absolute value of a phase difference between the first electrical current and the second electrical current is in a range from about 90 degrees to about 180 degrees.

10. The apparatus according to claim 1 , wherein the third alternating current electrical power source is configured such that an absolute value of a phase difference between the first electrical current and the third electrical current is in a range from about 90 degrees to about 180 degrees.

11. A method for forming a glass article, comprising:
supplying a first electrical current from a first alternating current electrical power source, a first portion of the first electrical current extending along a first electrical current path between a first electrode and a second electrode in a melting space of a melting vessel, the melting space comprising molten glass and a precious metal component in contact with the molten glass, the first electrical current path extending through the molten glass and not the precious metal component, and a second portion of the first electrical current extending along a second electrical current path between the first electrode and the second electrode in the melting space of the melting vessel, the second electrical current path extending through the molten glass and the precious metal component;
supplying a second electrical current out of phase with the first electrical current from a second alternating current electrical power source, the second electrical current extending between at least one of the first electrode or a first auxiliary electrode in contact with the molten glass and spaced apart from the first electrode, and the precious metal component; and
supplying a third electrical current out of phase with the first electrical current from a third alternating current electrical power source, the third electrical current extending between at least one of the second electrode or a second auxiliary electrode in contact with the molten glass and spaced apart from the second electrode, and the precious metal component.

12. The method according to claim 11 , wherein an absolute value of a phase difference between the first electrical current and the second electrical current is in a range from about 90 degrees to about 180 degrees.

13. The method according to claim 11 , wherein an absolute value of a phase difference between the first electrical current and the third electrical current is in a range from about 90 degrees to about 180 degrees.

14. The method according to claim 11 , wherein the second electrical current is in-phase with the third electrical current.

15. The method according to claim 11 , wherein a magnitude of the second electrical current in the precious metal component is in a range from about 50% to about 100% of a magnitude of the second portion of the first electrical current in the precious metal component.

16. The method according to claim 11 , wherein a magnitude of the third electrical current in the precious metal component is in a range from about 50% to about 100% of a magnitude of the second portion of the first electrical current in the precious metal component.

17. The method according to claim 11 , wherein a magnitude of the second electrical current in the precious metal component is substantially equal to a magnitude of the third electrical current in the precious metal component.

18. The method according to claim 11 , wherein the precious metal component comprises platinum.

19. The method according to claim 11 , wherein the precious metal component comprises at least one of a thermocouple, a bubbler tube, or a conduit configured as a flow path for the molten glass.

20. The method according to claim 11 , further comprising drawing the molten glass from a forming body to produce the glass article.

Assignees

• Corning Inc

Inventors

• Biswas Samir
• Hade Aaron Joshua
• Lineman David Myron
• Moshier Steven Robert
• Ryan Nicholas Scott

Classifications

• H05B3/03

  Electrodes · CPC title

• C03B33/0235

  Ribbons · CPC title

• C03B5/027 Primary

  by passing an electric current between electrodes immersed in the glass bath, i.e. by direct resistance heating · CPC title

• C03B18/02

  Forming sheets · CPC title

• C03B17/06

  Forming glass sheets · CPC title