Theoritical analysis of affecting factors upon operational resistance in the Powdex shows that the main causes leading to rapid increase of pressure difference in the Powdex are as follows:the content of suspended matter in influent water is high

the proportion of small particle size in powdered resin is large

and the pollution of filtering elements.For this

some effective methods for shut-down equipment conservation can be utilized

the proportion of small particle size in the powdered resin being controlled within a reasonable range

the polluted filtering elements being chemically cleaned or replaced.After implementation of the above-memtioned measures onto 2×600 MW units in one power plant of Shaanxi Province

the pressure difference and periodic operation time of the powdex already can satisfy the requirements of units in operation.