Abstract: A filtering sector (1) provided with two generating elements (2), obtained preferentially of polymeric material highly resistant to abrasion of mining products finely dispersed in the liquid filtrate, drained through the bi-foliar permeable film element (3), which covers the two grating elements (2), which are provided with lowered cylindrical holes (4) distributed along its extension, a par of grating elements (2) this one united through self-locking pins (5) which receives internally, through its frontal end, a locking counter-pin (11). Each grating element (2) formed by perimeter element (16) has a large edge (21) and, in the internal funneling of the grating elements (2), inserts (26), preferentially elastomeric or polymeric of high resistance to abrasion of the minerals finely disperse in the drained filtrate.