... Irrigation,Water treatment,Industry. This Automatic Backwashing Screen Filter is hydraulic-driven filter Model PHF, which is an automatic self cleaning ... approximately 20 seconds. Upon completion of the cleaning processthe filter returns to its initial position.This self cleaning flushing ... timer backup or manual. Available in the following inlet sizes: 4", 6", 8", 10", 12", 14", 16" ,18" and 20". Also ...