METHOD FOR HOMOGENIZING GLASS

• US 20200131071A1
• Filed: 10/24/2019
• Published: 04/30/2020
• Est. Priority Date: 10/26/2018
• Status: Active Grant

• Current Assignee: Heraeus Quarzglas GmbH & Co. KG (Heraeus Holding GMBH)
• Original Assignee: Heraeus Quarzglas GmbH & Co. KG (Heraeus Holding GMBH)
• Inventors: Thomas, Stephan, Vydra, Jan, Trommer, Martin, Huenermann, Michael, Langner, Andreas, Lehmann, Walter, Hengster, Stefan, Becker, Klaus
• Granted Patent: US 11,485,671 B2
• Time in Patent Office: Days
• CPC Class Codes: C03B 19/066 for the production of quartz or fused silica articles other processes specially adapted for the production of quartz or fused silica articles C03B20/00
• CPC Class Codes: C03B 19/1453 Thermal after-treatment of the shaped article, e.g. dehydrating, consolidating, sintering
• CPC Class Codes: C03B 19/1469 Means for changing or stabilising the shape or form of the shaped article or deposit
• CPC Class Codes: C03B 23/04 Re-forming tubes or rods
• CPC Class Codes: C03B 23/045 Tools or apparatus specially adapted for re-forming tubes or rods in general, e.g. glass lathes, chucks C03B23/043 takes precedence
• CPC Class Codes: C03B 32/00 Thermal after-treatment of glass products not provided for in groups C03B19/00 , C03B25/00 - C03B31/00 or C03B37/00, e.g. crystallisation, eliminating gas inclusions or other impurities; Hot-pressing vitrified, non-porous, shaped glass products

Abstract

A method for homogenizing glass includes the method: providing a cylindrical blank composed of the glass having a cylindrical outer surface that extends along a longitudinal axis of the blank between a first end face and a second end face, forming a shear zone in the blank by softening a longitudinal section of the blank and subjecting it to a thermal-mechanical intermixing treatment, and displacing the shear zone along the longitudinal axis of the blank. To enable a radial mixing within the shear zone in addition to the tangential mixing with the lowest possible time and energy input, starting from this method, cylindrical sections of the blank are adjacent to the shear zone on both sides, the first cylindrical section having a first central axis and the second cylindrical section having a second central axis, the first central axis and the second central axis being temporarily non-coaxial with each other.

Claims

1. A method for homogenizing glass, comprising:

(a) providing a cylindrical blank composed of the glass having a cylindrical outer surface that extends along a longitudinal axis of the blank over a length of the blank between a first end face and a second end face;

(b) forming a shear zone in the blank by softening a longitudinal section of the blank and subjecting it to a thermal-mechanical intermixing treatment; and

(c) displacing the shear zone along the longitudinal axis of the blank, wherein cylindrical sections of the blank are adjacent to the shear zone on both sides, the first cylindrical section having a first central axis and the second cylindrical section having a second central axis, the first central axis and the second central axis being at least temporarily non-coaxial with each other.

2. The method according to claim 1, wherein the first central axis and the second central axis are offset relative to each other at least at times.

3. The method according to claim 2, wherein the central axis offset is adjusted to a value in the range of between 0.5% and 15% of the diameter of the blank.

4. The method according to claim 2, wherein at least the first central axis additionally extends with an offset relative to a first machine rotation axis around which it is rotated.

5. The method according to claim 3, wherein at least the first central axis additionally extends with an offset relative to a first machine rotation axis around which it is rotated.

6. The method according to claim 2, wherein the first cylindrical section is rotated around the first axis of machine rotation and the second cylindrical section is rotated around a second axis of machine rotation, wherein the first and the second axis of rotation extend parallel to each other and are offset relative to each other.

7. The method according to claim 3, wherein the first cylindrical section is rotated around the first axis of machine rotation and the second cylindrical section is rotated around a second axis of machine rotation, wherein the first and the second axis of rotation extend parallel to each other and are offset relative to each other.

8. The method according to claim 1, wherein the first central axis and the second central axis are tilted relative to each other at least at times or run skew to each other at times, wherein the first cylindrical section is rotated around the first central axis and the second cylindrical section is rotated around the second central axis.

9. The method according to claim 8, wherein the cylindrical sections extend obliquely downwards, starting from the shear zone.

10. The method according to claim 8, wherein the cylindrical sections are oriented such that they extend obliquely upwards, starting from the shear zone.

11. The method according to claim 1, wherein the blank has a diameter D and that the shear zone has a width that is less than 0.3×

D.

12. The method according to claim 1, wherein the shear zone is at least partly surrounded by a thermal radiation dissipator, the lateral dimension of which, in the direction of the longitudinal axis of the blank, is greater than the shear zone and smaller than the length of the blank, wherein the thermal radiation dissipator is moved along the longitudinal axis of the blank synchronously with the shear zone.

19. The method according to claim 13, wherein the method further comprises a combination of the method according to claim 1.

13. A method for homogenizing glass, comprising:

(a) providing a cylindrical blank composed of the glass having a cylindrical outer surface that extends along a longitudinal axis of the blank over a length of the blank between a first end face and a second end face;

(b) forming a shear zone in the blank by softening a longitudinal section of the blank and subjecting it to a thermal-mechanical intermixing treatment; and

(c) displacing the shear zone along the longitudinal axis of the blank, wherein the displacement of the shear zone along the longitudinal axis of the blank is superimposed at least at times with an oscillating motion of the shear zone along the longitudinal axis of the blank.

14. The method according to claim 13, wherein the first end of the blank is rotated at a first rotational speed and the second end of the blank is rotated at a second rotational speed, wherein an oscillating motion of the shear zone is generated by periodically varying the first and/or second rotational speed.

15. The method according to claim 13, wherein the displacement of the shear zone along the longitudinal axis of the blank is caused by linear axial translational movement of a heat source along the longitudinal axis of the blank, wherein an oscillating motion of the shear zone is generated by superimposing a reversing motion of the heat source on the translational motion.

16. The method according to claim 14, wherein the displacement of the shear zone along the longitudinal axis of the blank is caused by linear axial translational movement of a heat source along the longitudinal axis of the blank, wherein an oscillating motion of the shear zone is generated by superimposing a reversing motion of the heat source on the translational motion.

17. The method according to claim 13, wherein the blank has a diameter D and that the shear zone has a width that is less than 0.3×

D.

18. The method according to claim 13, wherein the shear zone is at least partly surrounded by a thermal radiation dissipator, the lateral dimension of which, in the direction of the longitudinal axis of the blank, is greater than the shear zone and smaller than the length of the blank, wherein the thermal radiation dissipator is moved along the longitudinal axis of the blank synchronously with the shear zone.