SCREW PRESS TYPE SLUDGE DEHYDRATOR

PURPOSE:To suppress excessive formation of scale over the entire length of a screw shaft by providing a device for heating the high-pressure part on the large-diameter end side of the screw shaft to a sludge dehydrator provided with the screw shaft driven to rotate in a filter cylinder. CONSTITUTION:A screw shaft 4 fixed concentrically with a truncated circular cone cylinder 6 to a shaft 5 is passed through the inside of a filter cylinder 1 perforated with many filter holes 2 on the cylinder wall and screw vanes 7 are projected on the outside circumferential surface of the cylinder 6. The shaft 5 is driven to rotate by a chain transmission mechanism 9 and sludge is charged through a charge port 11 on the small-diameter side of the shaft 4 and is discharged through a discharge port 12 on the large-diameter side. An electrical heater 15 is attached between the high-pressure part of about 1/3 the large- diameter side of the cylinder 6 and the shaft 5 and a conductor 16 is connected via a slip ring 17 to an external power source to heat the part 8. A deodorizing cover 18 is put on the outside circumference and trays 19, 20 for receiving filtrate are successively provided. Generation of a large amt. of scale over the entire length of the screw shaft is thus obviated and the deterioration in the quality of sludge is prevented.