Screw centrifuge for solids-liq. sepn. - has compression devices for sludge post-dewatering

摘要

A screw centrifuge for solids/liq. sepn. has a cylindrical and opt. conical drum housing with solids and liq. discharge openings and has a clarification portion in which the pre-dewatered sludge is subjected to post-dewatering during transport by the screw to the solids discharge opening. Post-dewatering is effected by one or more sludge-compression devices located between the conveyor screw and the drum housing. The compression device may be a spiral plate or pressure rollers arranged between the turns of the screw, pressure pads connected to pressure medium supply lines and mounted between and/or on the screw threads, or inclined plates which are fixed on the inner drum wall to form tapering gaps. The periphery of the compression zone, i.e. the drum housing, the compression device and/or the screw threads, pref. (partially) comprises liq. permeable walls. ADVANTAGE - Additional mechanical compression esp. of finely particulate sludges is achieved to increase the dry solids content of the solid discharge e.g. from 44% to 60%.