A multi-structure filtration device for filtering, separating, and dehydrating foreign substances in water, the multi-structure filtration device comprising:
- a filtration tank filled with filtration target fluid inside;
- a filtration device unit having a cylindrical double drum structure, installed in the filtration tank so that a part of the filtration device unit is submerged in the filtration target fluid, and including a first filter and a second filter having different mesh sizes, the first filter being wound on an outside of the filtration device unit and the second filter being wound on an inside of the filtration device and having a finer mesh size than the first filter;
- a first washing module configured to transfer the first filter wound on the outside of the filtration device unit to an upper portion of the filtration tank outside of the filtration target fluid and configured to wash foreign substances attached to the first filter;
- a driving gear transmitting power to the first washing module;
- a second washing module configured to wash foreign substances attached to the second filter wound on the inside of the filtration device unit;
- a discharging module provided in the filtration device unit and configured to discharge floating foreign substances, which are generated during washing by the second washing module, to the first filter wound on the outside of the filtration device unit;
- and
- a control module configured to control operation states of the driving gear and the second washing module,
- wherein the control module is configured to operate the filtration device unit to double-filter foreign substances introduced into the filtration tank by collecting the foreign substances primarily through the first filter wound on the outside of the filtration device unit and then secondarily through the second filter wound on the inside of the filtration device unit,
- wherein when a preset time period elapses from a start time of filtration, the control module is configured to operate the first and second washing modules to wash the first and second filters by removing and separating foreign substances attached to the first and second filters,
- wherein the foreign substances removed and separated by the second washing module are detached and guided to the first filter wound on the outside of the filtration device unit through the discharging module, and the first filter is transferred to the first washing module of the filtration device unit along with filtered foreign substances, and then is washed,
- wherein the first washing module includes:
- an absorption roller configured to transport the first filter in a wound state and to absorb moisture contained in the foreign substances;
- a pressing roller configured to engage with the absorption roller and rotate in an opposite direction to a direction of transporting the first filter to remove and separate the foreign substances from the first filter;
- and
- a dehydration roller configured to press the absorption roller in a state of meeting with the absorption roller,
- wherein the absorption roller has a plurality of protrusions formed on an outer circumferential surface thereof, wherein the protrusion has a cylindrical or protruding shape, and a valley having a predetermined curve is formed between the protrusions,
- wherein when viewed from a side, the protrusion has a smooth curved end and is formed to extend along a longitudinal direction of the absorption roller.