摘要 |
A filter apparatus comprising a gravitional extraction section 1 and a high pressure section 3. In the high pressure section 3 there is a rotatable drum 35 around which a pair of filter bands 4,5 on carrier belts 6,7 are advanced with means for applying pressure to the belts to squeeze the bands and belts together to expel water from the sludge 13 through open-topped channels formed in the carrier belts. An intermediate section 2 for applying medium pressure to the sludge may be provided and the bands and belts are continuous. Various special features like cleaning, different pressure loading systems, and driving means and other modifications are described but the principle is to progressively increase the pressure by advancing the sludge between the belt and carrier assembly and to arrange for the water expelled to be diverted through the channels 8,9 in the carrier belts with no frictional drag between the respective bands and belts as they advance at the same speed. |