Patent ID: 8806892
Filing Date: 2014-08-19
Classification: C03B,Y02P

Abstract:
1. A method of manufacturing a vitreous silica crucible comprising: a silica powder supplying process of supplying a material silica powder into a mold for molding a vitreous silica crucible, to form a silica powder layer, and an arc fusing process of arc fusing the silica powder layer by arc discharge generated by carbon electrodes, wherein the arc fusing process includes processes of measuring a temperature of the silica powder layer with a radiation thermometer; obtaining a temperature at a local maximum point specific to the silica powder layer, said local maximum point appearing first in the arc fusing process where, after rising, the temperature starts to fall; then setting a temperature for controlling a vitreous silica fused state with reference to the temperature at the local maximum point used as a reference temperature; and controlling a vitreous silica fused state based on the set temperature, in the process of measuring a temperature of the silica powder layer, the temperature of the silica powder layer is measured where an observation line connecting the radiation thermometer and each temperature-measuring point on the silica powder layer is separated by 100 mm or more from the carbon electrodes, and the process of measuring a temperature of the silica powder layer includes measuring the temperature of the silica powder layer at a corner portion of the vitreous silica crucible.