APPARATUS FOR FORMING VITREOUS INNER LAYER ON FUSED SILICA BODY, AND METHOD FOR OPERATING THE SAME

PROBLEM TO BE SOLVED: To provide an apparatus for forming a vitreous inner layer on a fused silica body, and to provide a method for operating the same.SOLUTION: The apparatus for forming the layer 112 of vitreous silica adjacent to at least a portion of an inner surface of a fused silica body 102 includes a heat source 104 disposed to apply sufficient heat to at least a portion of the inner surface to vitrify a layer of the at least a portion of the inner surface. In one embodiment, the heat source 104 is configured to heat at one time a relatively small area 114 of the inner surface, and the apparatus includes a positioning mechanism for moving the heat source with respect to the inner surface. In another embodiment, the heat source is a hydrogen-oxygen surface-mix fueled torch 104 that is moved helically with respect to the inner surface 102 of the body by the control of a programmed CNC motion control system.