Patent ID: 7371320

Claim:
A magnetic separation unit comprising: an air-core solenoid type magnet having an air core at its center portion; a water passing pipe guiding, from a lower side, treated water including magnetic flocs in which contaminants and magnetic particles are flocculated and passing through the air core of said air-core solenoid type magnet; a rotating disc type magnetic filter attracting the magnetic flocs in the treated water supplied from said water passing pipe, said rotating disc type magnetic filter provided above said air-core solenoid type magnet; and flushing means for flushing the magnetic flocs attracted by said rotating disc type magnetic filter, wherein said water passing pipe has a small-diameter pipe section positioned in the air core of said air-core solenoid type magnet that guides the treated water from the lower side; and an enlarged pipe section positioned in the air core of said air-core solenoid type magnet that is gradually enlarged from said small-diameter pipe section toward a water passing part of said rotating disc type magnetic filter.