ULTRAVIOLET IRRADIATION APPARATUS USING DEVITRIFICATION RESISTANT GLASS

摘要

PURPOSE: To extend a functional life by making a material for a glass pipe through which water to be treated is passed from silica glass which meets specified conditions, contains a deficiency type defect amount of a specified value or more, and has viscosity of a specified value or more at a specified temperature. ;CONSTITUTION: An ultraviolet irradiation apparatus 1 is composed of a cylindrical sealed container 2 in which gas is sealed, two pairs of electrodes 3 placed in the container 2, and four glass pipes 4 for passing water W to be treated. Glass lining is applied to the outer surface of the electrodes 3. A cooling agent is passed through the internal void 3a of the electrodes 3. Devitrification resistant glass is used for the glass pipe 4. In the glass, the concentration of a contained immovable OH group and the concentration of a contained alkali earth metal element are regulated at specified values or below respectively, aluminum element is contained at concentration in a specified range, viscosity about 10 poise or more at 1100°C is secured, oxygen deficiency type defects about 5×10^-2cm^-1 or more in absorption coefficient of 250nm absorption band is contained.;COPYRIGHT: (C)1996,JPO