Patent ID: 9221709
Filing Date: 2015-12-29
Classification: C03B,C03C

Abstract:
1. An apparatus for vitrifying at least a portion of an inner surface of a fused silica body, the apparatus comprising: a turntable configured to rotate the fused silica body about a first longitudinal axis; a local area heat source comprising a boom defining a second longitudinal axis and a torch head coupled to a distal end of the boom, the local area heat source configured to apply heat to the at least a portion of the inner surface, the heat having a temperature sufficient to vitrify the portion of the inner surface; at least one positioning mechanism coupled to a proximal end of the boom of the local area heat source; and a controller coupled to the at least one positioning mechanism to command movement of the at least one positioning mechanism, wherein: the at least one positioning mechanism is configured to translate the local area heat source in a direction parallel to the first longitudinal axis, the at least one positioning mechanism is configured to translate the local area heat source along a radial axis orthogonal to the longitudinal axis to maintain a constant standoff distance between the torch head of the local area heat source and the portion of the inner surface as the local area heat source translates in the direction parallel to the longitudinal axis, the at least one positioning mechanism is configured to rotate the local area heat source about a tangential axis orthogonal to both the longitudinal axis and the radial axis to maintain the local area heat source perpendicular to the portion of the inner surface in a plane defined by the radial axis and the longitudinal axis as the local area heat source translates in the direction parallel to the longitudinal axis, and the at least one positioning mechanism is configured to rotate the local area heat source about the second longitudinal axis such that the torch head of the local area heat source is canted toward an approaching portion of the inner surface and the torch head of the local area heat source defines an obtuse angle relative to the portion of the inner surface in a plane defined by the radial axis and the tangential axis.