This press de-waters carbonaceous, finely-divided solids, especially sewage sludges and lignite, using heat and pressure. Superheated steam, in conjunction with mechanical surface pressure, is applied to the raw material within a pressure chamber. The pressure chamber is rectangular, comprising a fixed, lower press plate, and five, hydraulically actuated walls. There are two pressure strips along the side length of the lower press plate, which are urged by variable hydraulic force against the smooth long edges of the upper press plate. A hydraulically actuated motion advances and retracts a blocking slide at the inlet and outlet. The top press plate, acting between the vertical walls, presses and seals against steam injection under hydraulically applied force. Steam injection and water drainage take place in conjunction with a metal fabric belt above, and a distribution band below, located between the plates as described in DE 195 35 315.3. In this new development, the upper belt (44) runs endlessly around the upper press bar (63). Upper and lower (4) bands each pass through a wash station (43, 58). The steam blocking and sealing technology at the inlet and outlet (26, 27) of the pressure chamber (40) comprises a block slide (49) moving in and out at the outlet (27) and a blocking plate (52) moving at the inlet (26).