STRAINER

PURPOSE:To enable to remove all foreign matters by a structure wherein a directional control valve to select one of two compartments at the upstream side of a cylindrical filter net and wash water leading-out pipes capable of allowing and stopping the flow therein are connected to the compartments respectively in various strainers used in condenser and the like. CONSTITUTION:During normal use, the directional control valve 4 is directed straight axially so that the sea water is led into both the compartments A and B, which are divided with a partition plate 5, and simultaneously past through the filter net 3 and then led through a connecting tube 12 out of the strainer. When the filter net 3 is loaded, at first, the directional control valve 4 is directed to a compartment A side and a blow-out valve 10 is open in order to flow the stream at the compartment A side backward or from the inner side of the filter net 3 to the outer side, resulting in removing foreign matters adhered to the compartment A side and discharging through the blow-out valve 10 to the outside of the system. Next, the back-washing of the compartment B is similarly performed. Accordingly, foreign matters except shell-fishes are also completely cleared by back-flowing.