PURPOSE: To increase a life of filtration by increasing a period of filtration in the inside, by dividing a precoating operation into operations before raw water treating and during raw water treating.
CONSTITUTION: 0.1W2% Powdered ion-exchange resin is charged into a resin tank 17, and then is fed into a filtering cylinder 16 by a pump while sufficiently mixing with demineralized water by an agitator 18 to precoat the surfaces of elements 15 with the resin. When the elements 15 are almost precoated with the resin contained in the tank 17, raw water is fed to the cylinder 16 to start a treatment. After starting the treatment, the pressure difference between the outlet and inlet ports of the cylinder 16 is detected by pressure sensors 21 and 23, and when the pressure difference begins to rise rapidly, a controlling box 24 actuates a precoating pump 19 to feed the resin, previously agitated in the tank 17, to the cylinder 16 in order to coat the precoated layer of the elements 15 again thereby forming another layer of filter medium.
NISHIMURA SHIGEOKI
OGAWA TOSHIO
EBARA KATSUYA
TAKAHASHI SANKICHI
IZUMI KENKICHI
KUBOTA SHIYOUJI
TAKASHIMA YOSHIE
NUMAZAKI SEIICHI