| 摘要 |
PROBLEM TO BE SOLVED: To suppress vaporization of platinum group metal from a wall surface made of platinum group metal by a clarification apparatus for molten glass made of a material including platinum group metal at least partially while prolonging the lifetime of the clarification apparatus.SOLUTION: A clarification apparatus used for a manufacturing method for glass substrate includes a metal pipe which has a liquid phase of molten glass and a vapor phase space formed of the liquid level of the molten glass and an inner wall, at least a part of the inner wall surrounding the vapor phase space being made of a material including platinum group metal; and a heat insulation structure which surrounds the metal pipe and retains the warmth of the metal pipe. The molten glass is made to flow in the metal pipe of the clarification apparatus to achieve clarification. In the clarification, the heat insulation structure retains the warmth of the metal pipe so that the temperature of an upper surface of the metal pipe in contact with the vapor phase space is lower than a temperature at which vaporization of the platinum group metal is accelerated. |
