| 摘要 |
<p>A production method of quartz glass comprising the step of producing a soot deposit (5) including an effective portion that is formed by depositing soot produced by the flame hydrolysis of material gas on a starting member (2) pulled up while being rotated, has an almost constant outer diameter, and can be used as the material of a glass product, and non-effective portions (51, 52) that are formed at the opposite ends of the effective portion and have outer diameters changing in a taper form, wherein the method further comprises the step of forming the effective portion while rotating the starting member (2) and the soot deposit (5) at a rotation speed suitable for producing the effective portion after the outer diameter of the soot deposit (5) is stabilized, and the step of forming the non-effective portion (51) during the interval between the start of depositing soot on the starting member (2) and the stabilization of the outer diameter of the soot deposit (5) with a peripheral speed at the surface of the starting member (2) kept at up to 2.0m/min, or the step of forming the non-effective portion (52) while reducing a peripheral speed at the surface of the starting member (2) at a rate of 1. 3m/min per second to a final peripheral speed during a period after the effective portion is formed and until the rotation of the starting member (2) and the soot deposit (5) stops.</p> |
