Patent
Method and device for refining a glass melt using negative pressure
| العنوان: | Method and device for refining a glass melt using negative pressure |
|---|---|
| Patent Number: | 7,231,788 |
| تاريخ النشر: | June 19, 2007 |
| Appl. No: | 10/415772 |
| Application Filed: | October 23, 2001 |
| مستخلص: | The apparatus for reduced-pressure refining of a glass melt includes a refining bank formed so that a reduced pressure is generated by a glass flow in it. The refining bank has a component, which is made from a refractory metal or refractory alloy acting as glass-contact material. The refractory metal or alloy contains molybdenum, tungsten, tantalum, and/or hafnium. The device of the present invention includes a protective gas reservoir for a protective gas and an automatically operating valve connecting the reservoir with the refining bank so that an inner side of the component that would otherwise be exposed when a pressure rise or a falling glass melt column occurs is protected from oxidation by the protective gas. A process for using the device during refining of the glass melt is also part of the invention. |
| Inventors: | Karetta, Frank (Dittelsheim-Hessloch, DE); Witte, Joerg (Darmstadt, DE); Duch, Klaus-Dieter (Taunusstein, DE); Gohlke, Dirk (Meerscbuch, DE); Muench, Wolfgang (Bubenheim, DE); Jakway, Allen (Mainz, DE); Eichholz, Rainer (Mainz, DE); Lentes, Frank-Thomas (Bingen, DE) |
| Assignees: | Schott AG (Mainz, DE) |
| Claim: | 1. A device for reduced-pressure refining of a glass melt using a reduced-pressure apparatus in which the glass melt is fed to a refining bank via a riser and is discharged again from the refining bank via a downpipe so that a reduced pressure is generated by a glass flow in the refining bank, wherein said refining bank, said riser, and/or said downpipe comprises at least one component, said at least one component is made from a refractory metal or a refractory metal alloy acting as glass-contact material, and said refractory metal or said refractory metal alloy contains at least one of said molybdenum, said tungsten, said tantalum, and said hafnium; wherein said device comprises a protective gas reservoir and an automatic connection for connecting said protective gas reservoir to supply a protective gas to protect an inner side of said at least one component from oxidation in the event of a pressure rise or in the event of a falling glass melt column. |
| Claim: | 2. The device as defined in claim 1 , wherein said automatic connection comprises an automatically operable valve that automatically opens in response to said pressure rise or in response to said falling glass melt column so that said protective gas is automatically supplied to protect said inner side of said at least one component. |
| Claim: | 3. The device as defined in claim 1 , wherein said at least one component consists of said refractory metal. |
| Claim: | 4. The device as defined in claim 1 , wherein said at least one component comprises said tantalum or said hafnium. |
| Claim: | 5. The device as claimed in claim 1 , wherein a side of said at least one component remote from another side of the at least one component contacted by said glass melt is protected by purging with said protective gas or a forming gas. |
| Claim: | 6. The device as claimed in claim 1 , further comprising glazing a side of said at least one component remote from the glass melt in order to protect said at least one component from oxidation. |
| Claim: | 7. The device as claimed in claim 1 , wherein said at least one component is of a vacuum-tight design. |
| Claim: | 8. The device as claimed in claim 1 , wherein said at least one component is mechanically stable with respect to pressure differences. |
| Claim: | 9. The device as claimed in claim 1 , wherein said at least one component comprises individual pipe sections and said individual pipe sections are connected to one another by a flange connection or a screw connection. |
| Claim: | 10. The device as claimed in claim 9 , wherein said flange connection or said screw connection is made gas-tight by means of cutting edges. |
| Claim: | 11. The device as claimed in claim 9 , wherein said individual pipe sections connected to one another are annealed at high temperatures, so that contact locations between the pipe sections are welded or sintered together. |
| Claim: | 12. The device as claimed in claim 1 , wherein said at least one component is located in a housing. |
| Claim: | 13. The device as claimed in claim 12 , wherein said housing is gas-tight. |
| Claim: | 14. The device as claimed in claim 12 , further comprising means for compensating for thermal expansion of said at least one component with respect to said housing. |
| Claim: | 15. The device as claimed in claim 14 , wherein said means for compensating for thermal expansion comprises a spring-assisted bellows and said housing comprises said spring-assisted bellows. |
| Claim: | 16. The device as claimed in claim 1 , further comprising means for heating said at least one component. |
| Claim: | 17. The device as claimed in claim 16 , wherein said means for heating said at least one component comprises at least one radiation heater. |
| Claim: | 18. The device as claimed in claim 17 , wherein said at least one radiation heater is protected from oxidation by flushing said at least one radiation heater with said protective gas or a forming gas. |
| Claim: | 19. The device as claimed in claim 17 , wherein said at least one radiation heater is protected from oxidation by glazing. |
| Claim: | 20. The device as claimed in claim 16 , wherein said means for heating comprises means for inductive heating said at least one component. |
| Claim: | 21. The device as claimed in claim 16 , wherein said means for heating said at least one component comprises means for passing a high-frequency alternating current through said at least one component. |
| Claim: | 22. The device as claimed in claim 16 , wherein said means for heating said at least one component comprises means for providing a direct flow of current in said glass melt between a central stick electrode and said at least one component, wherein said at least one component acts as counter electrode. |
| Claim: | 23. A process for reduced-pressure refining of a glass melt in a reduced-pressure apparatus comprising a refining bank for the glass melt, a riser for supplying the glass melt to the refining bank, and a downpipe for discharge of the glass melt from the refining bank, wherein said refining bank, said riser, and/or said downpipe comprises at least one component made from at least one refractory metal or a refractory metal alloy acting as glass-contact material, said at least one refractory metal is selected from the group consisting of molybdenum, tungsten, tantalum, and hafnium, and said refractory metal alloy contains at least one of said molybdenum, said tungsten, said tantalum, and said hafnium, so that said at least one component contacts the glass melt; said process comprising the steps of: a) feeding a glass melt to be refined to the refining bank via the riser; b) generating a reduced pressure in the refining bank by means of a glass flow in the refining bank; and c) supplying a protective gas from a protective reservoir via an automatic connection to protect an inner side of the at least one component from oxidation when a pressure rise or a fall of a glass melt column occurs. |
| Claim: | 24. The process as defined in claim 23 , wherein said refining bank includes said at least one component and said automatic connection comprises an automatically opening valve that opens to supply said refining bank with said protective gas in the event of said pressure rise or said fall of the glass melt column. |
| Claim: | 25. The process as defined in claim 23 , wherein said protective gas comprises an inert gas or a reducing gas. |
| Claim: | 26. The process as defined in claim 23 , wherein said at least one component consists of said refractory metal. |
| Claim: | 27. The process as defined in claim 23 , further comprising heating said at least one component during said refining. |
| Claim: | 28. The process as defined in claim 27 , further comprising compensating for thermal expansion of said at least one component during said heating. |
| Current U.S. Class: | 651/342 |
| Patent References Cited: | 1598308 August 1926 Pike 3519412 July 1970 Olink 4351664 September 1982 Bansal 6460376 October 2002 Jeanvoine et al. 33 20 980 December 1984 33 20 980 December 1984 0 908 417 April 1999 0 918 417 April 1999 172 610 September 1922 |
| Other References: | Patent Abstracts of Japan vol. 14, No. 531, Nov. 21, 1990 & JP 02 221129 A, Sep. 4, 1990. cited by other Patent Abstracts of Japan vol. 2000, No. 06, Sep. 22, 2000 & JP 2000 086249 A, Mar. 28, 2000. cited by other Patent Abstracts of Japan vol. 2000, No. 12, Jan. 3, 2001 & JP 2000 247647 A, Sep. 12, 2000. cited by other Database WPI, Section Ch, Week 16, Derwent Publications Ltd., London, GB, AN 1998-177524 XP 002188856 & RU 2 087 428 A, Aug. 20, 1997. cited by other |
| Primary Examiner: | Hug, Eric |
| Attorney, Agent or Firm: | Striker, Michael J. |
| رقم الانضمام: | edspgr.07231788 |
| قاعدة البيانات: | USPTO Patent Grants |
| الوصف غير متاح. |