Abstract: This centrifugal apparatus comprises a primary frusto-conical filter screen rotating about a vertical axis, which is closed at its smaller diameter end and which is surrounded at its larger diameter upper end by a flat horizontal imperforate ring. A secondary cylindrical filter screen is fixed to and upstands from the periphery of the flat imperforate ring. The solid-liquid mixture is fed to the bottom of the primary filter screen and moves up under centrifugal force, the liquid being filtered and discharged into a surrounding casing. The solids move onto the ring and the liquid is further filtered through the secondary filter screen which retains the solids, being cylindrical. After the desired humidity content of the solids is reached, a scraper is lowered onto the ring to scrape the surface of the same and also the inner surface of the cylindrical secondary filter screen to remove the solids.