Sludge dryer

The invention relates to a sludge drying machine, which comprises a drying cylinder, a main shaft arranged in the drying cylinder, conveying blades spirally wound on the main shaft in the axial direction and a driving mechanism for driving the main shaft to rotate, a feeding port and a discharging port are formed in the two ends of the drying cylinder respectively, and the drying cylinder is vertically arranged. The main shaft is vertically arranged in the center of the drying cylinder, the conveying blades are provided with extrusion holes penetrating in the axial direction, wet sludge is extruded to the lower portion through the extrusion holes under the extrusion effect of the conveying blades in the upward conveying process, and a smashing assembly is arranged at the upper end of the drying cylinder. According to the sludge drying device, the extrusion holes are formed in the conveying blades, wherein the sludge with the high water content is extruded to the lower portion in the spiral conveying process o