US 11,811,453 B2
Upward collapse process and apparatus for making glass preforms
Qiulin Ma, Alpharetta, GA (US); Kai Huei Chang, Decatur, GA (US); Evan P. Green, Lawrenceville, GA (US); James E. Beavers, Jr., Flowery Branch, GA (US); and Carl W. Ponader, Buford, GA (US)
Assigned to HERAEUS QUARTZ NORTH AMERICA LLC, Buford, GA (US)
Filed by Heraeus Quartz North America LLC, Buford, GA (US)
Filed on May 25, 2022, as Appl. No. 17/824,477.
Application 17/824,477 is a division of application No. 15/813,669, filed on Nov. 15, 2017, granted, now 11,405,107.
Claims priority of provisional application 62/425,274, filed on Nov. 22, 2016.
Prior Publication US 2022/0286204 A1, Sep. 8, 2022
Int. Cl. C03B 37/012 (2006.01); H04B 10/2507 (2013.01); G01B 11/08 (2006.01); G01B 11/25 (2006.01); G02B 6/02 (2006.01); G01N 21/41 (2006.01); G06T 7/60 (2017.01)
CPC H04B 10/2507 (2013.01) [C03B 37/0126 (2013.01); C03B 37/01211 (2013.01); C03B 37/01245 (2013.01); C03B 37/01248 (2013.01); G01B 11/08 (2013.01); G01B 11/25 (2013.01); G02B 6/02 (2013.01); G01N 21/412 (2013.01); G06T 7/60 (2013.01); Y02P 40/57 (2015.11)] 5 Claims
OG exemplary drawing
 
1. An apparatus for creating a glass preform from a glass body having a weight, a circumference, at least one free-standing stacked core rod, and a cladding surrounding the at least one core rod and being separated from the core rod by a gap, the apparatus comprising:
a top collar affixed to a top of the cladding, the top collar having an outside diameter approximately the same as or smaller than an outside diameter of the cladding;
a bottom collar affixed to a bottom of the cladding, the bottom collar having an outside diameter either smaller than or approximately the same as the outside diameter of the cladding;
a bottom collar holder and vacuum unit holding and supporting the bottom collar, thereby supporting up to the entire weight of the glass body without contacting an outer surface of the glass body, the bottom collar holder and vacuum unit removing gas from or introducing gas to the apparatus;
a top collar holder and vacuum unit holding and supporting the top collar, the top collar holder and vacuum unit removing gas from or introducing gas to the apparatus;
a load cell for measuring a weight supported by the bottom collar, the top collar, or both; and
a frame defining a heating zone having a heating element to heat the glass body,
the bottom collar holder and vacuum unit being adapted to be moved at a controlled velocity V1 in a vertical direction and the top collar holder and vacuum unit being adapted to be moved at a controlled velocity V2 in the vertical direction such that when a vacuum is applied from either the bottom collar holder and vacuum unit or the top collar holder and vacuum unit, the top collar, the cladding, and the core rods can be collapsed to form the glass preform,
wherein the apparatus is configured to superimpose a constant oscillation perturbation onto the velocity V2 such that ripples appear on a measurement by the load cell reflecting a viscosity of the glass body at a center of the heating element.