Multicage-type device for filtering ballast water for preventing back pressure

A multi-cage type ballast water filtering device having a back pressure prevention structure, the device comprising:

• a body having an inlet port and an outlet port through which ballast water is drawn into and discharged from the body;
• and a plurality of filtering units connected to each other to form a packaged structure in the body,
• wherein each of the filtering units comprises:
• a filter filtering ballast water that flows through the body;
• and an automatic washing unit backwashing the filter to remove foreign substances adhering to the filter,
• the automatic washing unit comprises:
• a drive unit operating the automatic washing unit in response to a signal of a control unit;
• a suction unit connected to and moved by the drive unit, the suction unit sucking the foreign substances from the filter;
• and a discharge unit discharging the foreign substances sucked by the suction unit, and
• the discharge unit comprises a back pressure prevention tank provided on a backwash line so that backwash water and foreign substances drawn into the backwash line are primarily stored in the back pressure prevention tank, whereby back pressure in the backwash line is prevented from increasing.