| 摘要 |
PURPOSE:To enable high accuracy quartz pipes to be manufactured over a long term by carrying out drawing while preventing glass from contacting with the glass outflow portion of a mold or a crucible and the tip of a mandrel by spouting an inert gas from many small holes made in the glass outflow portion and the glass contacting face of the mandrel tip. CONSTITUTION:Circular opening 8 is composed of the glass outflow portion of mold 4 and the tip of mandrel 5, and an inert gas such as Ar gas is introduced from gas ducts 9, 10 and spouted from many small holes 4A, 5A made in the outflow portion and the glass contacting face of the mandrel tip to isolate opening 8 from molten glass 3. Glass 3 keeps a fixed distance from the glass outflow portion and the mandreal tip by the pressure of the gas from holes 4A, 5A, preventing the oxidation consumption and erosion of both the portions determining the size of a quartz pipe manufactured. The life of the portions are elongated remarkably, and the dimensional accuracy of the quartz pipe is enhanced remarkably. |
