| 摘要 |
PROBLEM TO BE SOLVED: To provide a secondary pure water making apparatus not lowering water quality by metalic colloids or fine particles generated from a metalic material constituting a feed water pump, a heat exchange, or an UV irradiator or the secondary pure water making apparatus and capable of stably obtaining ultrapure water of high quality with a residual ion concentration of 10 ng/L or less. SOLUTION: A filter 20 having ion exchange capacity capable of removing fine particles with a particle size of 5 μm or more is arranged between the feed water pump 11 and UF film separator 15 of the secondary pure water making apparatus. Metal colloids or fine particles are efficiently collected and removed by this filter 20 and, even if the collected metal colloids or fine particles are ionized, they can be adsorbed by the ion exchange capacity of the filter 20 to be held. Therefore, the ion leak due to the metal colloids or fine particles is prevented and ultrapure water of high quality can be stably obtained. |
