Arc discharge apparatus, apparatus and method for manufacturing vitreous silica glass crucible, and method for pulling up silicon single crystal
View Patent ↗The arc discharge apparatus comprises a plurality of carbon electrodes connected to respective phases of a power supply for heating a silica powder and causing it to fuse by generating arc discharge between the carbon electrodes. All of the carbon electrodes have a density in a range from 1.30 g/cm 3 to 1.80 g/cm 3 , and variability in density among the carbon electrodes is 0.2 g/cm 3 or less. The carbon particles that constitute the carbon electrodes preferably have a particle diameter of 0.3 mm or less.
1. An arc discharge apparatus having a plurality of carbon electrodes connected to respective phases of a power supply for heating a silica powder and causing it to fuse by generating arc discharge between the carbon electrodes, wherein all of the carbon electrodes have a density in a range of from 1.30 g/cm 3 to 1.57 g/cm 3 , and variability in density among the carbon electrodes of 0.2 g/cm 3 or less.
2. The arc discharge apparatus according to claim 1 , wherein the carbon electrodes are formed from carbon particles having a particle diameter of 0.3 mm or less.
3. The arc discharge apparatus according to claim 1 , wherein the variability in density among the carbon electrodes is 0.10 g/cm 3 or less and the carbon particles constituting the carbon electrodes have a particle diameter of 0.1 mm or less.
4. A vitreous silica glass crucible manufacturing apparatus comprising the arc discharge apparatus according to claim 1 and a mold that holds the silica powder.