| 摘要 |
PURPOSE:To always satisfy the required amount of ultrapure water in use points by controlling the discharge flow rate of a first-system circulation pump or controlling r.p.m. of the circulation pump and controlling r.p.m. of a feed- water pump so that a second system is made to become target pressure. CONSTITUTION:A first system having a closed loop is constituted by connecting a circulation pump 3, an ultraviolet irradiator 6, a cartridge polisher 7 and a membrane treatment device 8 in series and the residual ultrapure water consumed in use points 8 is series and the residual ultrapure water consumed in use points 9 is returned to the inlet side of the pump 3 and also a second system for directly feeding pure water sent from a replenishment water pump 12 of a primary pure water producing device to the circulation pump 3 is constituted. The discharge flow rate of the circulation pump 3 is set at constant with a flow rate setting valve 4. The pressure P1 in the inlet side of the circulation pump 3 is fluctuated by consumption of ultrapure pure water in the use points 9 and this is detected with a pressure detector 21 and r.p.m. of the replenishment water pump 12 is controlled with a controlling device 22 so that the pressure P1 in the inlet side is made equal to the target pressure P2. |
