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US 5,698,484 AGranted
Method and containment vessel for producing fused silica glass and the fused silica blank produced
AssigneeCorning Incorporated
InventorJohn E. Maxon
Life of this patent
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AssigneeCorning Incorporated
InventorJohn E. Maxon
Estimating the term…
Fused silica boules (19) having improved homogeneity are produced by causing the boule (19) to flow radially during its formation to achieve local mixing between portions of the boule which may have experienced different laydown conditions. The mixing is achieved by one or a combination of: (1) use of a containment vessel (13) having a gently sloping containment wall (22); (2) use of a containment vessel (13) whose inner radius (r.sub.v) is substantially larger than the outermost radius (r.sub.b) of the burners (14) used to produce the boule (19); and/or (3) maintaining the boule (19) at a sufficiently high temperature during laydown so that radial flow is achieved with a minimum head height of glass. Large blanks having high homogeneity can be made from such boules, e.g., blanks having diameters above 200 millimeters and .DELTA.n values of less than 0.25.times.10.sup.-6.
A method for forming a silica-containing body, said body having a center and said method comprising:
A containment vessel for use in forming a silica-containing body, said vessel comprising a bottom which is covered with bait sand and at least one containment wall which contacts the body as the body is formed, the vertical height of said wall increasing with increasing distance from the center of the vessel at a rate which is less than or equal to about 3.
A furnace for forming a silica-containing body comprising:
A fused silica blank which has a homogeneity which is less than or equal to 0.25.times.10.sup.-6 for a blank size greater than or equal to 125 millimeters.
The fused silica blank of claim 37 wherein the blank size is greater than or equal to 200 millimeters.
Dependencies are inferred from the claim text.